User
   +-------------------------------------------------------------+
   |                            CCXT                             |
   +------------------------------+------------------------------+
   |            Public            |           Private            |
   +=============================================================+
   │                              .                              |
   │                    The Unified CCXT API                     |
   │                              .                              |
   |       loadMarkets            .           fetchBalance       |
   |       fetchMarkets           .            createOrder       |
   |       fetchCurrencies        .            cancelOrder       |
   |       fetchTicker            .             fetchOrder       |
   |       fetchTickers           .            fetchOrders       |
   |       fetchOrderBook         .        fetchOpenOrders       |
   |       fetchOHLCV             .      fetchClosedOrders       |
   |       fetchStatus            .          fetchMyTrades       |
   |       fetchTrades            .                deposit       |
   |                              .               withdraw       |
   │                              .                              |
   +=============================================================+
   │                              .                              |
   |                     Custom Exchange API                     |
   |         (Derived Classes And Their Implicit Methods)        |
   │                              .                              |
   |       publicGet...           .          privateGet...       |
   |       publicPost...          .         privatePost...       |
   |                              .          privatePut...       |
   |                              .       privateDelete...       |
   |                              .                   sign       |
   │                              .                              |
   +=============================================================+
   │                              .                              |
   |                      Base Exchange Class                    |
   │                              .                              |
   +=============================================================+

 import logging
 logging.basicConfig(level=logging.DEBUG)

 * 
  `has`: An assoc-array containing flags for exchange capabilities, including the following:

  .. code-block:: JavaScript

       'has': {

           'CORS': false,  // has Cross-Origin Resource Sharing enabled (works from browser) or not

           'publicAPI': true,  // has public API available and implemented, true/false
           'privateAPI': true, // has private API available and implemented, true/false

           // unified methods availability flags (can be true, false, or 'emulated'):

           'cancelOrder': true,
           'createDepositAddress': false,
           'createOrder': true,
           'fetchBalance': true,
           'fetchCanceledOrders': false,
           'fetchClosedOrder': false,
           'fetchClosedOrders': false,
           'fetchCurrencies': false,
           'fetchDepositAddress': false,
           'fetchMarkets': true,
           'fetchMyTrades': false,
           'fetchOHLCV': false,
           'fetchOpenOrder': false,
           'fetchOpenOrders': false,
           'fetchOrder': false,
           'fetchOrderBook': true,
           'fetchOrders': false,
           'fetchStatus': 'emulated',
           'fetchTicker': true,
           'fetchTickers': false,
           'fetchBidsAsks': false,
           'fetchTrades': true,
           'withdraw': false,
           ...
       }

    The meaning of each flag showing availability of this or that method is:


  * a value of ``undefined`` / ``None`` / ``null`` means the method is not currently implemented in ccxt (either ccxt has not unified it yet or the method isn't natively available from the exchange API)
  * boolean ``false`` specifically means that the endpoint isn't natively available from the exchange API
  * boolean ``true`` means the endpoint is natively available from the exchange API and unified in the ccxt library
  * 
    ``'emulated'`` string means the endpoint isn't natively available from the exchange API but reconstructed (as much as possible) by the ccxt library from other available true-methods

    For a complete list of all exchages and their supported methods, please, refer to this example: https://github.com/ccxt/ccxt/blob/master/examples/js/exchange-capabilities.js

Rate Limit
----------

Exchanges usually impose what is called a *rate limit*. Exchanges will remember and track your user credentials and your IP address and will not allow you to query the API too frequently. They balance their load and control traffic congestion to protect API servers from (D)DoS and misuse.

 **WARNING: Stay under the rate limit to avoid ban!**

Most exchanges allow **up to 1 or 2 requests per second**. Exchanges may temporarily restrict your access to their API or ban you for some period of time if you are too aggressive with your requests.

 **The ``exchange.rateLimit`` property is set to a safe default which is sub-optimal. Some exchanges may have varying rate limits for different endpoints. It is up to the user to tweak ``rateLimit`` according to application-specific purposes.**

The CCXT library has a built-in experimental rate-limiter that will do the necessary throttling in background transparently to the user. **WARNING: users are responsible for at least some type of rate-limiting: either by implementing a custom algorithm or by doing it with the built-in rate-limiter.**.

Turn on/off the built-in rate-limiter with ``.enableRateLimit`` property, like so:

.. code-block:: JavaScript

   // JavaScript

   // enable built-in rate limiting upon instantiation of the exchange
   const exchange = new ccxt.bitfinex ({
       // 'enableRateLimit': true, // enabled by default
   })

   // or switch the built-in rate-limiter on or off later after instantiation
   exchange.enableRateLimit = true // enable
   exchange.enableRateLimit = false // disable

.. code-block:: Python

   # Python

   # enable built-in rate limiting upon instantiation of the exchange
   exchange = ccxt.bitfinex({
       # 'enableRateLimit': True,  # enabled by default
   })

   # or switch the built-in rate-limiter on or off later after instantiation
   exchange.enableRateLimit = True  # enable
   exchange.enableRateLimit = False  # disable

.. code-block:: PHP

   // PHP

   // enable built-in rate limiting upon instantiation of the exchange
   $exchange = new \ccxt\bitfinex (array (
       // 'enableRateLimit' => true, // enabled by default
   ));

   // or switch the built-in rate-limiter on or off later after instantiation
   $exchange->enableRateLimit = true; // enable
   $exchange->enableRateLimit = false; // disable

In case your calls hit a rate limit or get nonce errors, the ccxt library will throw an ``InvalidNonce`` exception, or, in some cases, one of the following types:


 * ``DDoSProtection``
 * ``ExchangeNotAvailable``
 * ``ExchangeError``
 * ``InvalidNonce``

A later retry is usually enough to handle that.

Notes On Rate Limiter
^^^^^^^^^^^^^^^^^^^^^

The rate limiter is a property of the exchange instance, in other words, each exchange instance has its own rate limiter that is not aware of the other instances. In many cases the user should reuse the same exchange instance throughout the program. Do not use multiple instances of the same exchange with the same API keypair from the same IP address.

.. code-block:: JavaScript

   // DO NOT DO THIS!

   const binance1 = new ccxt.binance ({ enableRateLimit: true })
   const binance2 = new ccxt.binance ({ enableRateLimit: true })
   const binance3 = new ccxt.binance ({ enableRateLimit: true })

   while (true) {
       const result = await Promise.all ([
           binance1.fetchOrderBook ('BTC/USDT'),
           binance2.fetchOrderBook ('ETH/USDT'),
           binance3.fetchOrderBook ('ETH/BTC'),
       ])
       console.log (result)
   }

Reuse the exchange instance as much as possible as shown below:

.. code-block:: JavaScript

   // DO THIS INSTEAD:

   const binance = new ccxt.binance ({ enableRateLimit: true })

   while (true) {
       const result = await Promise.all ([
           binance.fetchOrderBook ('BTC/USDT'),
           binance.fetchOrderBook ('ETH/USDT'),
           binance.fetchOrderBook ('ETH/BTC'),
       ])
       console.log (result)
   }

Since the rate limiter belongs to the exchange instance, destroying the exchange instance will destroy the rate limiter as well. Among the most common pitfalls with the rate limiting is creating and dropping the exchange instance over and over again. If in your program you are creating and destroying the exchange instance (say, inside a function that is called multiple times), then you are effectively resetting the rate limiter over and over and that will eventually break the rate limits. If you are recreating the exchange instance every time instead of reusing it, CCXT will try to load the markets every time. Therefore, you will force-load the markets over and over as explained in the `Loading Markets <https://docs.ccxt.com/en/latest/manual.html#loading-markets>`__ section. Abusing the markets endpoint will eventually break the rate limiter as well.

.. code-block:: JavaScript

   // DO NOT DO THIS!

   async function tick () {
       const exchange = new ccxt.binance ({ enableRateLimit: true })
       const response = await exchange.fetchOrderBook ('BTC/USDT')
       // ... some processing here ...
       return response
   }

   while (true) {
       const result = await tick ()
       console.log (result)
   }

Do not break this rule unless you really understand the inner workings of the rate-limiter and you are 100% sure you know what you're doing. In order to stay safe always reuse the exchange instance throughout your functions and methods callchain like shown below:

.. code-block:: JavaScript

   // DO THIS INSTEAD:

   async function tick (exchange) {
       const response = await exchange.fetchOrderBook ('BTC/USDT')
       // ... some processing here ...
       return response
   }

   const exchange = new ccxt.binance ({ enableRateLimit: true })
   while (true) {
       const result = await tick (exchange)
       console.log (result)
   }

DDoS Protection By Cloudflare / Incapsula
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Some exchanges are `DDoS <https://en.wikipedia.org/wiki/Denial-of-service_attack>`__\ -protected by `Cloudflare <https://www.cloudflare.com>`__ or `Incapsula <https://www.incapsula.com>`__. Your IP can get temporarily blocked during periods of high load. Sometimes they even restrict whole countries and regions. In that case their servers usually return a page that states a HTTP 40x error or runs an AJAX test of your browser / captcha test and delays the reload of the page for several seconds. Then your browser/fingerprint is granted access temporarily and gets added to a whitelist or receives a HTTP cookie for further use.

The most common symptoms for a DDoS protection problem, rate-limiting problem or for a location-based filtering issue:


 * Getting ``RequestTimeout`` exceptions with all types of exchange methods
 * Catching ``ExchangeError`` or ``ExchangeNotAvailable`` with HTTP error codes 400, 403, 404, 429, 500, 501, 503, etc..
 * Having DNS resolving issues, SSL certificate issues and low-level connectivity issues
 * Getting a template HTML page instead of JSON from the exchange

If you encounter DDoS protection errors and cannot reach a particular exchange then:


 * use a proxy (this is less responsive, though)
 * ask the exchange support to add you to a whitelist
 * try an alternative IP within a different geographic region
 * run your software in a distributed network of servers
 * run your software in close proximity to the exchange (same country, same city, same datacenter, same server rack, same server)
 * ...

Markets
=======



Each exchange is a place for trading some kinds of valuables. The exchanges may use differing terms to call them: *"a currency"*\ , *"an asset"*\ , *"a coin"*\ , *"a token"*\ , *"stock"*\ , *"commodity"*\ , *"crypto"*\ , "fiat", etc. A place for trading one asset for another is usually called *"a market"*\ , *"a symbol"*\ , *"a trading pair"*\ , *"a contract"*\ , etc.

In terms of the ccxt library, every exchange offers multiple **markets** within itself. Each market is defined by two or more **currencies**. The set of markets differs from exchange to exchange opening possibilities for cross-exchange and cross-market arbitrage.

Currency Structure
------------------

.. code-block:: JavaScript

   {
       'id':       'btc',       // string literal for referencing within an exchange
       'code':     'BTC',       // uppercase unified string literal code the currency
       'name':     'Bitcoin',   // string, human-readable name, if specified
       'active':    true,       // boolean, currency status (tradeable and withdrawable)
       'fee':       0.123,      // withdrawal fee, flat
       'precision': 8,          // number of decimal digits "after the dot" (depends on exchange.precisionMode)
       'deposit':   true        // boolean, deposits are available
       'withdraw':  true        // boolean, withdraws are available
       'limits': {              // value limits when placing orders on this market
           'amount': {
               'min': 0.01,     // order amount should be > min
               'max': 1000,     // order amount should be < max
           },
           'withdraw': { ... }, // withdrawal limits
           'deposit': {...},
       },
       'networks': {...}        // network structures indexed by unified network identifiers (ERC20, TRC20, BSC, etc)
       'info': { ... },         // the original unparsed currency info from the exchange
   }

Each currency is an associative array (aka dictionary) with the following keys:


 * ``id``. The string or numeric ID of the currency within the exchange. Currency ids are used inside exchanges internally to identify coins during the request/response process.
 * ``code``. An uppercase string code representation of a particular currency. Currency codes are used to reference currencies within the ccxt library (explained below).
 * ``name``. A human-readable name of the currency (can be a mix of uppercase & lowercase characters).
 * ``fee``. The withdrawal fee value as specified by the exchange. In most cases it means a flat fixed amount paid in the same currency. If the exchnange does not specify it via public endpoints, the ``fee`` can be ``undefined/None/null`` or missing.
 * ``active``. A boolean indicating whether trading or funding (depositing or withdrawing) for this currency is currently possible, more about it here: :ref:`\ ``active`` status <active status>`.
 * ``info``. An associative array of non-common market properties, including fees, rates, limits and other general market information. The internal info array is different for each particular market, its contents depend on the exchange.
 * ``precision``. Precision accepted in values by exchanges upon referencing this currency. The value of this property depends on :ref:`\ ``exchange.precisionMode`` <precision mode>`.
 * ``limits``. The minimums and maximums for amounts (volumes), withdrawals and deposits.

Network structure
-----------------

.. code-block:: JavaScript

   {
       'id':       'tron',         // string literal for referencing within an exchange
       'network':  'TRC20'         // unified network
       'name':     'Tron Network', // string, human-readable name, if specified
       'active':    true,          // boolean, currency status (tradeable and withdrawable)
       'fee':       0.123,         // withdrawal fee, flat
       'precision': 8,             // number of decimal digits "after the dot" (depends on exchange.precisionMode)
       'deposit':   true           // boolean, deposits are available
       'withdraw':  true           // boolean, withdraws are available
       'limits': {                 // value limits when placing orders on this market
           'amount': {
               'min': 0.01,        // order amount should be > min
               'max': 1000,        // order amount should be < max
           },
           'withdraw': { ... },    // withdrawal limits
           'deposit': {...},       // deposit limits
       },
       'info': { ... },            // the original unparsed currency info from the exchange
   }

Each network is an associative array (aka dictionary) with the following keys:


 * ``id``. The string or numeric ID of the network within the exchange. Network ids are used inside exchanges internally to identify networks during the request/response process.
 * ``network``. An uppercase string representation of a particular network. Networks are used to reference networks within the ccxt library.
 * ``name``. A human-readable name of the network (can be a mix of uppercase & lowercase characters).
 * ``fee``. The withdrawal fee value as specified by the exchange. In most cases it means a flat fixed amount paid in the same currency. If the exchnange does not specify it via public endpoints, the ``fee`` can be ``undefined/None/null`` or missing.
 * ``active``. A boolean indicating whether trading or funding (depositing or withdrawing) for this currency is currently possible, more about it here: :ref:`\ ``active`` status <active status>`.
 * ``info``. An associative array of non-common market properties, including fees, rates, limits and other general market information. The internal info array is different for each particular market, its contents depend on the exchange.
 * ``precision``. Precision accepted in values by exchanges upon referencing this currency. The value of this property depends on :ref:`\ ``exchange.precisionMode`` <precision mode>`.
 * ``limits``. The minimums and maximums for amounts (volumes), withdrawals and deposits.

Market Structure
----------------

.. code-block:: JavaScript

   {
       'id':      'btcusd',      // string literal for referencing within an exchange
       'symbol':  'BTC/USD',     // uppercase string literal of a pair of currencies
       'base':    'BTC',         // uppercase string, unified base currency code, 3 or more letters
       'quote':   'USD',         // uppercase string, unified quote currency code, 3 or more letters
       'baseId':  'btc',         // any string, exchange-specific base currency id
       'quoteId': 'usd',         // any string, exchange-specific quote currency id
       'active':   true,         // boolean, market status
       'type':    'spot',        // spot for spot, future for expiry futures, swap for perpetual swaps, 'option' for options
       'spot':     true,         // whether the market is a spot market
       'margin':   true,         // whether the market is a margin market
       'future':   false,        // whether the market is a expiring future
       'swap':     false,        // whether the market is a perpetual swap
       'option':   false,        // whether the market is an option contract
       'contract': false,        // whether the market is a future, a perpetual swap, or an option
       'settle':   'USDT',       // the unified currency code that the contract will settle in, only set if `contract` is true
       'settleId': 'usdt',       // the currencyId of that the contract will settle in, only set if `contract` is true
       'contractSize': 1,        // the size of one contract, only used if `contract` is true
       'linear':   true,         // the contract is a linear contract (settled in quote currency)
       'inverse':  false,        // the contract is an inverse contract (settled in base currency)
       'expiry':  1641370465121, // the unix expiry timestamp in milliseconds, undefined for everything except market['type'] `future`
       'expiryDatetime': '2022-03-26T00:00:00.000Z', // The datetime contract will in iso8601 format
       'strike': 4000,           // price at which a put or call option can be exercised
       'optionType': 'call',     // call or put string, call option represents an option with the right to buy and put an option with the right to sell
       'taker':    0.002,        // taker fee rate, 0.002 = 0.2%
       'maker':    0.0016,       // maker fee rate, 0.0016 = 0.16%
       'percentage': true,       // whether the taker and maker fee rate is a multiplier or a fixed flat amount
       'tierBased': false,       // whether the fee depends on your trading tier (your trading volume)
       'feeSide': 'get',         // string literal can be 'get', 'give', 'base', 'quote', 'other'
       'precision': {            // number of decimal digits "after the dot"
           'price': 8,           // integer or float for TICK_SIZE roundingMode, might be missing if not supplied by the exchange
           'amount': 8,          // integer, might be missing if not supplied by the exchange
           'cost': 8,            // integer, very few exchanges actually have it
       },
       'limits': {               // value limits when placing orders on this market
           'amount': {
               'min': 0.01,      // order amount should be > min
               'max': 1000,      // order amount should be < max
           },
           'price': { ... },     // same min/max limits for the price of the order
           'cost':  { ... },     // same limits for order cost = price * amount
           'leverage': { ... },  // same min/max limits for the leverage of the order
       },
       'info':      { ... },     // the original unparsed market info from the exchange
   }

Each market is an associative array (aka dictionary) with the following keys:


 * ``id``. The string or numeric ID of the market or trade instrument within the exchange. Market ids are used inside exchanges internally to identify trading pairs during the request/response process.
 * ``symbol``. An uppercase string code representation of a particular trading pair or instrument. This is usually written as ``BaseCurrency/QuoteCurrency`` with a slash as in ``BTC/USD``\ , ``LTC/CNY`` or ``ETH/EUR``\ , etc. Symbols are used to reference markets within the ccxt library (explained below).
 * ``base``. A unified uppercase string code of base fiat or crypto currency. This is the standardized currency code that is used to refer to that currency or token throughout CCXT and throughout the Unified CCXT API, it's the language that CCXT understands.
 * ``quote``. A unified uppercase string code of quoted fiat or crypto currency.
 * ``baseId``. An exchange-specific id of the base currency for this market, not unified. Can be any string, literally. This is communicated to the exchange using the language the exchange understands.
 * ``quoteId``. An exchange-specific id of the quote currency, not unified.
 * ``active``. A boolean indicating whether or not trading this market is currently possible, more about it here: :ref:`\ ``active`` status <active status>`.
 * ``maker``. Float, 0.0015 = 0.15%. Maker fees are paid when you provide liquidity to the exchange i.e. you *market-make* an order and someone else fills it. Maker fees are usually lower than taker fees. Fees can be negative, this is very common amongst derivative exchanges. A negative fee means the exchange will pay a rebate (reward) to the user for trading this market.
 * ``taker``. Float, 0.002 = 0.2%. Taker fees are paid when you *take* liquidity from the exchange and fill someone else's order.
 * ``percentage``. A boolean true/false value indicating whether ``taker`` and ``maker`` are multipliers or fixed flat amounts.
 * ``tierBased``. A boolean true/false value indicating whether the fee depends on your trading tier (usually, your traded volume over a period of time).
 * ``info``. An associative array of non-common market properties, including fees, rates, limits and other general market information. The internal info array is different for each particular market, its contents depend on the exchange.
 * ``precision``. Precision accepted in order values by exchanges upon order placement for price, amount and cost. (The value inside this property depend on the :ref:`\ ``exchange.precisionMode`` <precision mode>`\ ).
 * ``limits``. The minimums and maximums for prices, amounts (volumes) and costs (where cost = price * amount).
 * ``optionType``. The type of the option, ``call`` option represents an option with the right to buy and ``put`` an option with the right to sell.
 * ``strike``. Price at which an option can be bought or sold when it is exercised.

Active status
-------------

The ``active`` flag is typically used in :ref:`\ ``currencies`` <currency structure>` and :ref:`\ ``markets`` <market structure>`. The exchanges might put a slightly different meaning into it. If a currency is inactive, most of the time all corresponding tickers, orderbooks and other related endpoints return empty responses, all zeroes, no data or outdated information. The user should check if the currency is ``active`` and :ref:`reload markets periodically <market cache force reload>`.

Note: the ``false`` value for the ``active`` property doesn't always guarantee that all of the possible features like trading, withdrawing or depositing are disabled on the exchange. Likewise, neither the ``true`` value guarantees that all those features are enabled on the exchange. Check the underlying exchanges' documentation and the code in CCXT for the exact meaning of the ``active`` flag for this or that exchange. This flag is not yet supported or implemented by all markets and may be missing.

 **WARNING! The information about the fee is experimental, unstable and may be partial or not available at all.**

Precision And Limits
--------------------

 **Do not confuse ``limits`` with ``precision``\ !** Precision has nothing to do with min limits. A precision of 8 digits does not necessarily mean a min limit of 0.00000001. The opposite is also true: a min limit of 0.0001 does not necessarily mean a precision of 4.

Examples:


#. 

   ``(market['limits']['amount']['min'] == 0.05) && (market['precision']['amount'] == 4)``

   In this example the **amount** of any order placed on the market **must satisfy both conditions**\ :


   * The *amount value* should be >= 0.05:
     .. code-block:: diff

        + good: 0.05, 0.051, 0.0501, 0.0502, ..., 0.0599, 0.06, 0.0601, ...
        - bad: 0.04, 0.049, 0.0499

   * *Precision of the amount* should be up to 4 decimal digits:
     .. code-block:: diff

        + good: 0.05, 0.051, 0.052, ..., 0.0531, ..., 0.06, ... 0.0719, ...
        - bad: 0.05001, 0.05000, 0.06001

#. 

   ``(market['limits']['price']['min'] == 0.019) && (market['precision']['price'] == 5)``

   In this example the **price** of any order placed on the market **must satisfy both conditions**\ :


   * The *price value* should be >= 0.019:
     .. code-block:: diff

        + good: 0.019, ... 0.0191, ... 0.01911, 0.01912, ...
        - bad: 0.016, ..., 0.01699

   * *Precision of price* should be 5 decimal digits or less:
     .. code-block:: diff

        + good: 0.02, 0.021, 0.0212, 0.02123, 0.02124, 0.02125, ...
        - bad: 0.017000, 0.017001, ...

#. 

   ``(market['limits']['amount']['min'] == 50) && (market['precision']['amount'] == -1)``

   In this example **both conditions must be satisfied**\ :


   * The *amount value* should be greater than or equal to 50:
     .. code-block:: diff

        + good: 50, 60, 70, 80, 90, 100, ... 2000, ...
        - bad: 1, 2, 3, ..., 9

   * A negative *amount precision* means that the amount should be an integer multiple of 10 (to the absolute power specified):
     .. code-block:: diff

        + good: 50, ..., 110, ... 1230, ..., 1000000, ..., 1234560, ...
        - bad: 9.5, ... 10.1, ..., 11, ... 200.71, ...

 *The ``precision`` and ``limits`` params are currently under heavy development, some of these fields may be missing here and there until the unification process is complete. This does not influence most of the orders but can be significant in extreme cases of very large or very small orders.*

Notes On Precision And Limits

Each exchange has its own rounding, counting and padding modes.

Supported rounding modes are:


 * ``ROUND`` – will round the last decimal digits to precision
 * ``TRUNCATE``\ – will cut off the digits after certain precision

The decimal precision counting mode is available in the ``exchange.precisionMode`` property.

Precision Mode
""""""""""""""

Supported precision modes in ``exchange['precisionMode']`` are:


 * ``DECIMAL_PLACES`` – counts all digits, 99% of exchanges use this counting mode. With this mode of precision, the numbers in ``market_or_currency['precision']`` designate the number of decimal digits after the dot for further rounding or truncation.
 * ``SIGNIFICANT_DIGITS`` – counts non-zero digits only, some exchanges (\ ``bitfinex`` and maybe a few other) implement this mode of counting decimals. With this mode of precision, the numbers in ``market_or_currency['precision']`` designate the Nth place of the last significant (non-zero) decimal digit after the dot.
 * ``TICK_SIZE`` – some exchanges only allow a multiple of a specific value (\ ``bitmex`` and ``ftx`` use this mode, for example). In this mode, the numbers in ``market_or_currency['precision']`` designate the minimal precision fractions (floats) for rounding or truncating.

Padding Mode
""""""""""""

Supported padding modes are:


 * ``NO_PADDING`` – default for most cases
 * ``PAD_WITH_ZERO`` – appends zero characters up to precision

Formatting To Precision
"""""""""""""""""""""""

Most of the time the user does not have to take care of precision formatting, since CCXT will handle that for the user when the user places orders or sends withdrawal requests, if the user follows the rules as described on :ref:`Precision And Limits <precision and limits>`. However, in some cases precision-formatting details may be important, so the following methods may be useful in the userland.

The exchange base class contains the ``decimalToPrecision`` method to help format values to the required decimal precision with support for different rounding, counting and padding modes.

.. code-block:: JavaScript

   // JavaScript
   function decimalToPrecision (x, roundingMode, numPrecisionDigits, countingMode = DECIMAL_PLACES, paddingMode = NO_PADDING)

.. code-block:: Python

   # Python
   # WARNING! The `decimal_to_precision` method is susceptible to getcontext().prec!
   def decimal_to_precision(n, rounding_mode=ROUND, precision=None, counting_mode=DECIMAL_PLACES, padding_mode=NO_PADDING):

.. code-block:: PHP

   // PHP
   function decimalToPrecision ($x, $roundingMode = ROUND, $numPrecisionDigits = null, $countingMode = DECIMAL_PLACES, $paddingMode = NO_PADDING)

For examples of how to use the ``decimalToPrecision`` to format strings and floats, please, see the following files:


 * JavaScript: https://github.com/ccxt/ccxt/blob/master/js/test/base/functions/test.number.js
 * Python: https://github.com/ccxt/ccxt/blob/master/python/ccxt/test/test_decimal_to_precision.py
 * PHP: https://github.com/ccxt/ccxt/blob/master/php/test/decimal_to_precision.php

 **Python WARNING! The ``decimal_to_precision`` method is susceptible to ``getcontext().prec!``\ **

For users' convenience CCXT base exchange class also implements the following methods:

.. code-block:: JavaScript

   // JavaScript
   function amountToPrecision (symbol, amount)
   function priceToPrecision (symbol, price)
   function costToPrecision (symbol, cost)
   function currencyToPrecision (code, amount)

.. code-block:: Python

   # Python
   def amount_to_precision (symbol, amount):
   def price_to_precision (symbol, price):
   def cost_to_precision (symbol, cost):
   def currency_to_precision (code, amount):

.. code-block:: PHP

   // PHP
   function amount_to_precision($symbol, $amount)
   function price_to_precision($symbol, $price)
   function cost_to_precision($symbol, $cost)
   function currency_to_precision($code, $amount)

Every exchange has its own precision settings, the above methods will help format those values according to exchange-specific precision rules, in a way that is portable and agnostic of the underlying exchange. In order to make that possible, markets and currencies have to be loaded prior to formatting any values.

 **Make sure to :ref:`load the markets with ``exchange.loadMarkets()`` <loading markets>` before calling these methods!**

For example:

.. code-block:: JavaScript

   // JavaScript
   await exchange.loadMarkets ()
   const symbol = 'BTC/USDT'
   const amount = 1.2345678 // amount in base currency BTC
   const price = 87654.321 // price in quote currency USDT
   const formattedAmount = exchange.amountToPrecision (symbol, amount)
   const formattedPrice = exchange.priceToPrecision (symbol, price)
   console.log (formattedAmount, formattedPrice)

.. code-block:: Python

   # Python
   exchange.load_markets()
   symbol = 'BTC/USDT'
   amount = 1.2345678  # amount in base currency BTC
   price = 87654.321  # price in quote currency USDT
   formatted_amount = exchange.amount_to_precision(symbol, amount)
   formatted_price = exchange.price_to_precision(symbol, price)
   print(formatted_amount, formatted_price)

.. code-block:: PHP

   // PHP
   $exchange->load_markets();
   $symbol = 'BTC/USDT';
   $amount = 1.2345678;  // amount in base currency BTC
   $price = 87654.321; // price in quote currency USDT
   $formatted_amount = $exchange->amount_to_precision($symbol, $amount);
   $formatted_price = $exchange->price_to_precision($symbol, $price);
   echo $formatted_amount, " ", $formatted_price, "\n";

More practical examples that describe the behavior of ``exchange.precisionMode``\ :

.. code-block:: JavaScript

   // case A
   exchange.precisionMode = ccxt.DECIMAL_PLACES
   market = exchange.market (symbol)
   market['precision']['amount'] === 8 // up to 8 decimals after the dot
   exchange.amountToPrecision (symbol, 0.123456789) === 0.12345678
   exchange.amountToPrecision (symbol, 0.0000000000123456789) === 0.0000000 === 0.0

.. code-block:: JavaScript

   // case B
   exchange.precisionMode = ccxt.TICK_SIZE
   market = exchange.market (symbol)
   market['precision']['amount'] === 0.00000001 // up to 0.00000001 precision
   exchange.amountToPrecision (symbol, 0.123456789) === 0.12345678
   exchange.amountToPrecision (symbol, 0.0000000000123456789) === 0.00000000 === 0.0

.. code-block:: JavaScript

   // case C
   exchange.precisionMode = ccxt.SIGNIFICANT_DIGITS
   market = exchange.market (symbol)
   market['precision']['amount'] === 8 // up to 8 significant non-zero digits
   exchange.amountToPrecision (symbol, 0.0000000000123456789) === 0.000000000012345678
   exchange.amountToPrecision (symbol, 123.4567890123456789) === 123.45678

Loading Markets
---------------

In most cases you are required to load the list of markets and trading symbols for a particular exchange prior to accessing other API methods. If you forget to load markets the ccxt library will do that automatically upon your first call to the unified API. It will send two HTTP requests, first for markets and then the second one for other data, sequentially. For that reason, your first call to a unified CCXT API method like fetchTicker, fetchBalance, etc will take more time, than the consequent calls, since it has to do more work loading the market information from the exchange API. See `Notes On Rate Limiter <https://docs.ccxt.com/en/latest/manual.html#notes-on-rate-limiter>`__ for more details.

In order to load markets manually beforehand call the ``loadMarkets ()`` / ``load_markets ()`` method on an exchange instance. It returns an associative array of markets indexed by trading symbol. If you want more control over the execution of your logic, preloading markets by hand is recommended.

.. code-block:: JavaScript

   // JavaScript
   (async () => {
       let kraken = new ccxt.kraken ()
       let markets = await kraken.loadMarkets ()
       console.log (kraken.id, markets)
   }) ()

.. code-block:: Python

   # Python
   okcoin = ccxt.okcoinusd()
   markets = okcoin.load_markets()
   print(okcoin.id, markets)

.. code-block:: PHP

   // PHP
   $id = 'huobipro';
   $exchange = '\\ccxt\\' . $id;
   $huobipro = new $exchange();
   $markets = $huobipro->load_markets();
   var_dump($huobipro->id, $markets);

Apart from the market info, the ``loadMarkets()`` call will also load the currencies from the exchange and will cache the info in the ``.markets`` and the ``.currencies`` properties respectively.

The user can also bypass the cache and call unified methods for fetching that information from the exchange endpoints directly, ``fetchMarkets()`` and ``fetchCurrencies()``\ , though using these methods is not recommended for end-users. The recommended way to preload markets is by calling the ``loadMarkets()`` unified method. However, new exchange integrations are required to implement these methods if the underlying exchange has the corresponding API endpoints.

Symbols And Market Ids
----------------------

A currency code is a code of three to five letters, like ``BTC``\ , ``ETH``\ , ``USD``\ , ``GBP``\ , ``CNY``\ , ``JPY``\ , ``DOGE``\ , ``RUB``\ , ``ZEC``\ , ``XRP``\ , ``XMR``\ , etc. Some exchanges have exotic currencies with longer codes.

A symbol is usually an uppercase string literal name of a pair of traded currencies with a slash in between. The first currency before the slash is usually called *base currency*\ , and the one after the slash is called *quote currency*. Examples of a symbol are: ``BTC/USD``\ , ``DOGE/LTC``\ , ``ETH/EUR``\ , ``DASH/XRP``\ , ``BTC/CNY``\ , ``ZEC/XMR``\ , ``ETH/JPY``.

Market ids are used during the REST request-response process to reference trading pairs within exchanges. The set of market ids is unique per exchange and cannot be used across exchanges. For example, the BTC/USD pair/market may have different ids on various popular exchanges, like ``btcusd``\ , ``BTCUSD``\ , ``XBTUSD``\ , ``btc/usd``\ , ``42`` (numeric id), ``BTC/USD``\ , ``Btc/Usd``\ , ``tBTCUSD``\ , ``XXBTZUSD``. You don't need to remember or use market ids, they are there for internal HTTP request-response purposes inside exchange implementations.

The ccxt library abstracts uncommon market ids to symbols, standardized to a common format. Symbols aren't the same as market ids. Every market is referenced by a corresponding symbol. Symbols are common across exchanges which makes them suitable for arbitrage and many other things.

Sometimes the user might notice a symbol like ``'XBTM18'`` or ``'.XRPUSDM20180101'`` or some other *"exotic/rare symbols"*. The symbol is **not required** to have a slash or to be a pair of currencies. The string in the symbol really depends on the type of the market (whether it is a spot market or a futures market, a darkpool market or an expired market, etc). Attempting to parse the symbol string is highly discouraged, one should not rely on the symbol format, it is recommended to use market properties instead.

Market structures are indexed by symbols and ids. The base exchange class also has builtin methods for accessing markets by symbols. Most API methods require a symbol to be passed in their first argument. You are often required to specify a symbol when querying current prices, making orders, etc.

Most of the time users will be working with market symbols. You will get a standard userland exception if you access non-existent keys in these dicts.

Methods For Markets And Currencies
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   // JavaScript

   (async () => {

       console.log (await exchange.loadMarkets ())

       let btcusd1 = exchange.markets['BTC/USD']     // get market structure by symbol
       let btcusd2 = exchange.market ('BTC/USD')     // same result in a slightly different way

       let btcusdId = exchange.marketId ('BTC/USD')  // get market id by symbol

       let symbols = exchange.symbols                // get an array of symbols
       let symbols2 = Object.keys (exchange.markets) // same as previous line

       console.log (exchange.id, symbols)            // print all symbols

       let currencies = exchange.currencies          // a dictionary of currencies

       let bitfinex = new ccxt.bitfinex ()
       await bitfinex.loadMarkets ()

       bitfinex.markets['BTC/USD']                   // symbol → market (get market by symbol)
       bitfinex.markets_by_id['XRPBTC'][0]           // id → market (get market by id)

       bitfinex.markets['BTC/USD']['id']             // symbol → id (get id by symbol)
       bitfinex.markets_by_id['XRPBTC'][0]['symbol'] // id → symbol (get symbol by id)

   }) ()

.. code-block:: Python

   # Python

   print(exchange.load_markets())

   etheur1 = exchange.markets['ETH/EUR']         # get market structure by symbol
   etheur2 = exchange.market('ETH/EUR')          # same result in a slightly different way

   etheurId = exchange.market_id('ETH/EUR')      # get market id by symbol

   symbols = exchange.symbols                    # get a list of symbols
   symbols2 = list(exchange.markets.keys())      # same as previous line

   print(exchange.id, symbols)                   # print all symbols

   currencies = exchange.currencies              # a dictionary of currencies

   kraken = ccxt.kraken()
   kraken.load_markets()

   kraken.markets['BTC/USD']                     # symbol → market (get market by symbol)
   kraken.markets_by_id['XXRPZUSD'][0]           # id → market (get market by id)

   kraken.markets['BTC/USD']['id']               # symbol → id (get id by symbol)
   kraken.markets_by_id['XXRPZUSD'][0]['symbol'] # id → symbol (get symbol by id)

.. code-block:: PHP

   // PHP

   $var_dump($exchange->load_markets());

   $dashcny1 = $exchange->markets['DASH/CNY'];        // get market structure by symbol
   $dashcny2 = $exchange->market('DASH/CNY');         // same result in a slightly different way

   $dashcnyId = $exchange->market_id('DASH/CNY');     // get market id by symbol

   $symbols = $exchange->symbols;                     // get an array of symbols
   $symbols2 = array_keys($exchange->markets);        // same as previous line

   var_dump($exchange->id, $symbols);                 // print all symbols

   $currencies = $exchange->currencies;               // an associative array of currencies

   $okcoinusd = '\\ccxt\\okcoinusd';
   $okcoinusd = new $okcoinusd();

   $okcoinusd->load_markets();

   $okcoinusd->markets['BTC/USD'];                    // symbol → market (get market by symbol)
   $okcoinusd->markets_by_id['btc_usd'][0];              // id → market (get market by id)

   $okcoinusd->markets['BTC/USD']['id'];              // symbol → id (get id by symbol)
   $okcoinusd->markets_by_id['btc_usd'][0]['symbol']; // id → symbol (get symbol by id)

Naming Consistency
^^^^^^^^^^^^^^^^^^

There is a bit of term ambiguity across various exchanges that may cause confusion among newcoming traders. Some exchanges call markets as *pairs*\ , whereas other exchanges call symbols as *products*. In terms of the ccxt library, each exchange contains one or more trading markets. Each market has an id and a symbol. Most symbols are pairs of base currency and quote currency.

``Exchanges → Markets → Symbols → Currencies``

Historically various symbolic names have been used to designate same trading pairs. Some cryptocurrencies (like Dash) even changed their names more than once during their ongoing lifetime. For consistency across exchanges the ccxt library will perform the following known substitutions for symbols and currencies:


 * `XBT → BTC`: `XBT` is newer but `BTC` is more common among exchanges and sounds more like bitcoin ([read more](https://www.google.ru/search?q=xbt+vs+btc)).
 * `BCC → BCH`: The Bitcoin Cash fork is often called with two different symbolic names: ``BCC`` and ``BCH``. The name ``BCC`` is ambiguous for Bitcoin Cash, it is confused with BitConnect. The ccxt library will convert ``BCC`` to ``BCH`` where it is appropriate (some exchanges and aggregators confuse them).
 * `DRK → DASH`: `DASH` was Darkcoin then became Dash ([read more](https://minergate.com/blog/dashcoin-and-dash/)).
 * ``BCHABC → BCH``\ : On November 15 2018 Bitcoin Cash forked the second time, so, now there is ``BCH`` (for BCH ABC) and ``BSV`` (for BCH SV).
 * ``BCHSV → BSV``\ : This is a common substitution mapping for the Bitcoin Cash SV fork (some exchanges call it ``BSV``\ , others call it ``BCHSV``\ , we use the former).
 * ``DSH → DASH``\ : Try not to confuse symbols and currencies. The ``DSH`` (Dashcoin) is not the same as ``DASH`` (Dash). Some exchanges have ``DASH`` labelled inconsistently as ``DSH``\ , the ccxt library does a correction for that as well (\ ``DSH → DASH``\ ), but only on certain exchanges that have these two currencies confused, whereas most exchanges have them both correct. Just remember that ``DASH/BTC`` is not the same as ``DSH/BTC``.
 * ``XRB`` → `NANO`: `NANO` is the newer code for RaiBlocks, thus, CCXT unified API uses will replace the older `XRB` with `NANO` where needed. https://hackernoon.com/nano-rebrand-announcement-9101528a7b76
 * ``USD`` → ``USDT``\ : Some exchanges, like Bitfinex, HitBTC and a few other name the currency as ``USD`` in their listings, but those markets are actually trading ``USDT``. The confusion can come from a 3-letter limitation on symbol names or may be due to other reasons. In cases where the traded currency is actually ``USDT`` and is not ``USD`` – the CCXT library will perform ``USD`` → \ ``USDT`` conversion. Note, however, that some exchanges  have both ``USD`` and ``USDT`` symbols, for example, Kraken has a ``USDT/USD`` trading pair.

Notes On Naming Consistency
~~~~~~~~~~~~~~~~~~~~~~~~~~~

Each exchange has an associative array of substitutions for cryptocurrency symbolic codes in the ``exchange.commonCurrencies`` property. Sometimes the user may notice exotic symbol names with mixed-case words and spaces in the code. The logic behind having these names is explained by the rules for resolving conflicts in naming and currency-coding when one or more currencies have the same symbolic code with different exchanges:


 * First, we gather all info available from the exchanges themselves about the currency codes in question. They usually have a description of their coin listings somewhere in their API or their docs, knowledgebases or elsewhere on their websites.
 * When we identify each particular cryptocurrency standing behind the currency code, we look them up on `CoinMarketCap <https://coinmarketcap.com>`__.
 * The currency that has the greatest market capitalization of all wins the currency code and keeps it. For example, HOT often stand for either ``Holo`` or ``Hydro Protocol``. In this case ``Holo`` retains the code ``HOT``\ , and ``Hydro Protocol`` will have its name as its code, literally, ``Hydro Protocol``. So, there may be trading pairs with symbols like ``HOT/USD`` (for ``Holo``\ ) and ``Hydro Protocol/USD`` – those are two different markets.
 * If market cap of a particular coin is unknown or is not enough to determine the winner, we also take trading volumes and other factors into consideration.
 * When the winner is determined all other competing currencies get their code names properly remapped and substituted within conflicting exchanges via ``.commonCurrencies``.
 * Unfortunately this is a work in progress, because new currencies get listed daily and new exchanges are added from time to time, so, in general this is a never-ending process of self-correction in a quickly changing environment, practically, in *"live mode"*. We are thankful for all reported conflicts and mismatches you may find.

Questions On Naming Consistency

It depends on which exchange you are using, but some of them have a reversed (inconsistent) pairing of ``base`` and ``quote``. They actually have base and quote misplaced  (switched/reversed sides). In that case you'll see a difference of parsed ``base`` and ``quote`` currency values with the unparsed ``info`` in the market substructure.

For those exchanges the ccxt will do a correction, switching and normalizing sides of base and quote currencies when parsing exchange replies. This logic is financially and terminologically correct. If you want less confusion, remember the following rule: **base is always before the slash, quote is always after the slash in any symbol and with any market**.

.. code-block:: text

   base currency ↓
                BTC / USDT
                ETH / BTC
               DASH / ETH
                       ↑ quote currency

Contract Naming Conventions
~~~~~~~~~~~~~~~~~~~~~~~~~~~

We currently load spot markets with the unified ``BASE/QUOTE`` symbol schema into the ``.markets`` mapping, indexed by symbol. This would cause a naming conflict for futures and other derivatives that have the same symbol as their spot market counterparts. To accomodate both types of markets in the ``.markets`` we require the symbols between 'future' and 'spot' markets to be distinct, as well as the symbols between 'linear' and 'inverse' contracts to be distinct.

 **Please, check this announcement: `Unified contract naming conventions <https://github.com/ccxt/ccxt/issues/10931>`__

CCXT supports the following types of derivative contracts:


 * ``future`` – for expiring futures contracts that have a delivery/settlement date ` <https://en.wikipedia.org/wiki/Futures_contract>`__
 * ``swap`` – for perpetual swap futures that don't have a delivery date ` <https://en.wikipedia.org/wiki/Perpetual_futures>`__
 * ``option`` – for option contracts (https://en.wikipedia.org/wiki/Option_contract)

Future
""""""

A future market symbol consists of the underlying currency, the quoting currency, the settlement currency and an arbitrary identifier. Most often the identifier is the settlement date of the future contract in ``YYMMDD`` format:

.. code-block:: JavaScript

   //
   // base asset or currency
   // ↓
   // ↓  quote asset or currency
   // ↓  ↓
   // ↓  ↓    settlement asset or currency
   // ↓  ↓    ↓
   // ↓  ↓    ↓     identifier (settlement date)
   // ↓  ↓    ↓     ↓
   // ↓  ↓    ↓     ↓
   'BTC/USDT:BTC-211225'  // BTC/USDT futures contract settled in BTC (inverse) on 2021-12-25
   'BTC/USDT:USDT-211225' // BTC/USDT futures contract settled in USDT (linear, vanilla) on 2021-12-25
   'ETH/USDT:ETH-210625'  // ETH/USDT futures contract settled in ETH (inverse) on 2021-06-25
   'ETH/USDT:USDT-210625' // ETH/USDT futures contract settled in USDT (linear, vanilla) on 2021-06-25

Perpetual Swap (Perpetual Future)
"""""""""""""""""""""""""""""""""

.. code-block:: JavaScript

   // base asset or currency
   // ↓
   // ↓  quote asset or currency
   // ↓  ↓
   // ↓  ↓    settlement asset or currency
   // ↓  ↓    ↓
   // ↓  ↓    ↓
   'BTC/USDT:BTC'  // BTC/USDT inverse perpetual swap contract funded in BTC
   'BTC/USDT:USDT' // BTC/USDT linear perpetual swap contract funded in USDT
   'ETH/USDT:ETH'  // ETH/USDT inverse perpetual swap contract funded in ETH
   'ETH/USDT:USDT' // ETH/USDT linear perpetual swap contract funded in USDT

Option
""""""

.. code-block:: JavaScript

   //
   // base asset or currency
   // ↓
   // ↓  quote asset or currency
   // ↓  ↓
   // ↓  ↓    settlement asset or currency
   // ↓  ↓    ↓
   // ↓  ↓    ↓       identifier (settlement date)
   // ↓  ↓    ↓       ↓
   // ↓  ↓    ↓       ↓   strike price
   // ↓  ↓    ↓       ↓   ↓
   // ↓  ↓    ↓       ↓   ↓   type, put (P) or call (C)
   // ↓  ↓    ↓       ↓   ↓   ↓
   'BTC/USDT:BTC-211225-60000-P'  // BTC/USDT put option contract strike price 60000 USDT settled in BTC (inverse) on 2021-12-25
   'ETH/USDT:USDT-211225-40000-C' // BTC/USDT call option contract strike price 40000 USDT settled in USDT (linear, vanilla) on 2021-12-25
   'ETH/USDT:ETH-210625-5000-P'   // ETH/USDT put option contract strike price 5000 USDT settled in ETH (inverse) on 2021-06-25
   'ETH/USDT:USDT-210625-5000-C'  // ETH/USDT call option contract strike price 5000 USDT settled in USDT (linear, vanilla) on 2021-06-25

Market Cache Force Reload
-------------------------

The ``loadMarkets () / load_markets ()`` is also a dirty method with a side effect of saving the array of markets on the exchange instance. You only need to call it once per exchange. All subsequent calls to the same method will return the locally saved (cached) array of markets.

When exchange markets are loaded, you can then access market information any time via the ``markets`` property. This property contains an associative array of markets indexed by symbol. If you need to force reload the list of markets after you have them loaded already, pass the reload = true flag to the same method again.

.. code-block:: JavaScript

   // JavaScript
   (async () => {
       let kraken = new ccxt.kraken ({ verbose: true }) // log HTTP requests
       await kraken.loadMarkets () // request markets
       console.log (kraken.id, kraken.markets)    // output a full list of all loaded markets
       console.log (Object.keys (kraken.markets)) // output a short list of market symbols
       console.log (kraken.markets['BTC/USD'])    // output single market details
       await kraken.loadMarkets () // return a locally cached version, no reload
       let reloadedMarkets = await kraken.loadMarkets (true) // force HTTP reload = true
       console.log (reloadedMarkets['ETH/BTC'])
   }) ()

.. code-block:: Python

   # Python
   poloniex = ccxt.poloniex({'verbose': True}) # log HTTP requests
   poloniex.load_markets() # request markets
   print(poloniex.id, poloniex.markets)   # output a full list of all loaded markets
   print(list(poloniex.markets.keys())) # output a short list of market symbols
   print(poloniex.markets['BTC/ETH'])     # output single market details
   poloniex.load_markets() # return a locally cached version, no reload
   reloadedMarkets = poloniex.load_markets(True) # force HTTP reload = True
   print(reloadedMarkets['ETH/ZEC'])

.. code-block:: PHP

   // PHP
   $bitfinex = new \ccxt\bitfinex(array('verbose' => true)); // log HTTP requests
   $bitfinex.load_markets(); // request markets
   var_dump($bitfinex->id, $bitfinex->markets); // output a full list of all loaded markets
   var_dump(array_keys ($bitfinex->markets));   // output a short list of market symbols
   var_dump($bitfinex->markets['XRP/USD']);     // output single market details
   $bitfinex->load_markets(); // return a locally cached version, no reload
   $reloadedMarkets = $bitfinex->load_markets(true); // force HTTP reload = true
   var_dump($bitfinex->markets['XRP/BTC']);

Implicit API
============



API Methods / Endpoints
-----------------------

Each exchange offers a set of API methods. Each method of the API is called an *endpoint*. Endpoints are HTTP URLs for querying various types of information. All endpoints return JSON in response to client requests.

Usually, there is an endpoint for getting a list of markets from an exchange, an endpoint for retrieving an order book for a particular market, an endpoint for retrieving trade history, endpoints for placing and canceling orders, for money deposit and withdrawal, etc... Basically every kind of action you could perform within a particular exchange has a separate endpoint URL offered by the API.

Because the set of methods differs from exchange to exchange, the ccxt library implements the following:


 * a public and private API for all possible URLs and methods
 * a unified API supporting a subset of common methods

The endpoint URLs are predefined in the ``api`` property for each exchange. You don't have to override it, unless you are implementing a new exchange API (at least you should know what you're doing).

Most of exchange-specific API methods are implicit, meaning that they aren't defined explicitly anywhere in code. The library implements a declarative approach for defining implicit (non-unified) exchanges' API methods.

Implicit API Methods
--------------------

Each method of the API usually has its own endpoint. The library defines all endpoints for each particular exchange in the ``.api`` property. Upon exchange construction an implicit *magic* method (aka *partial function* or *closure*\ ) will be created inside ``defineRestApi()/define_rest_api()`` on the exchange instance for each endpoint from the list of ``.api`` endpoints. This is performed for all exchanges universally. Each generated method will be accessible in both ``camelCase`` and ``under_score`` notations.

The endpoints definition is a **full list of ALL API URLs** exposed by an exchange. This list gets converted to callable methods upon exchange instantiation. Each URL in the API endpoint list gets a corresponding callable method. This is done automatically for all exchanges, therefore the ccxt library supports **all possible URLs** offered by crypto exchanges.

Each implicit method gets a unique name which is constructed from the ``.api`` definition. For example, a private HTTPS PUT ``https://api.exchange.com/order/{id}/cancel`` endpoint will have a corresponding exchange method named ``.privatePutOrderIdCancel()``\ /\ ``.private_put_order_id_cancel()``. A public HTTPS GET ``https://api.exchange.com/market/ticker/{pair}`` endpoint would result in the corresponding method named ``.publicGetTickerPair()``\ /\ ``.public_get_ticker_pair()``\ , and so on.

An implicit method takes a dictionary of parameters, sends the request to the exchange and returns an exchange-specific JSON result from the API **as is, unparsed**. To pass a parameter, add it to the dictionary explicitly under a key equal to the parameter's name. For the examples above, this would look like ``.privatePutOrderIdCancel ({ id: '41987a2b-...' })`` and ``.publicGetTickerPair ({ pair: 'BTC/USD' })``.

The recommended way of working with exchanges is not using exchange-specific implicit methods but using the unified ccxt methods instead. The exchange-specific methods should be used as a fallback in cases when a corresponding unified method isn't available (yet).

To get a list of all available methods with an exchange instance, including implicit methods and unified methods you can simply do the following:

.. code-block:: text

   console.log (new ccxt.kraken ())   // JavaScript
   print(dir(ccxt.kraken()))           # Python
   var_dump (new \ccxt\kraken ()); // PHP

Public/Private API
------------------

API URLs are often grouped into two sets of methods called a *public API* for market data and a *private API* for trading and account access. These groups of API methods are usually prefixed with a word 'public' or 'private'.

A public API is used to access market data and does not require any authentication whatsoever. Most exchanges provide market data openly to all (under their rate limit). With the ccxt library anyone can access market data out of the box without having to register with the exchanges and without setting up account keys and passwords.

Public APIs include the following:


 * instruments/trading pairs
 * price feeds (exchange rates)
 * order books (L1, L2, L3...)
 * trade history (closed orders, transactions, executions)
 * tickers (spot / 24h price)
 * OHLCV series for charting
 * other public endpoints

The private API is mostly used for trading and for accessing account-specific private data, therefore it requires authentication. You have to get the private API keys from the exchanges. It often means registering with an exchange website and creating the API keys for your account. Most exchanges require personal information or identification. Some exchanges will only allow trading after completing the KYC verification.
Private APIs allow the following:


 * manage personal account info
 * query account balances
 * trade by making market and limit orders
 * create deposit addresses and fund accounts
 * request withdrawal of fiat and crypto funds
 * query personal open / closed orders
 * query positions in margin/leverage trading
 * get ledger history
 * transfer funds between accounts
 * use merchant services

Some exchanges offer the same logic under different names. For example, a public API is also often called *market data*\ , *basic*\ , *market*\ , *mapi*\ , *api*\ , *price*\ , etc... All of them mean a set of methods for accessing data available to public. A private API is also often called *trading*\ , *trade*\ , *tapi*\ , *exchange*\ , *account*\ , etc...

A few exchanges also expose a merchant API which allows you to create invoices and accept crypto and fiat payments from your clients. This kind of API is often called *merchant*\ , *wallet*\ , *payment*\ , *ecapi* (for e-commerce).

To get a list of all available methods with an exchange instance, you can simply do the following:

.. code-block:: text

   console.log (new ccxt.kraken ())   // JavaScript
   print(dir(ccxt.kraken()))           # Python
   var_dump (new \ccxt\kraken ()); // PHP

 **contract only and margin only**


 * methods in this documentation that are documented as **contract only** or **margin only** are only intended to be used for contract trading and margin trading respectively. They may work when trading in other types of markets but will most likely return irrelevant information.

Synchronous vs Asynchronous Calls
---------------------------------

JavaScript
^^^^^^^^^^

In the JavaScript version of CCXT all methods are asynchronous and return `Promises <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise>`__ that resolve with a decoded JSON object. In CCXT we use the modern *async/await* syntax to work with Promises. If you're not familiar with that syntax, you can read more about it `here <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function>`__.

.. code-block:: JavaScript

   // JavaScript

   (async () => {
       let pairs = await kraken.publicGetSymbolsDetails ()
       let marketIds = Object.keys (pairs['result'])
       let marketId = marketIds[0]
       let ticker = await kraken.publicGetTicker ({ pair: marketId })
       console.log (kraken.id, marketId, ticker)
   }) ()

Python
^^^^^^

The ccxt library supports asynchronous concurrency mode in Python 3.5+ with async/await syntax. The asynchronous Python version uses pure `asyncio <https://docs.python.org/3/library/asyncio.html>`__ with `aiohttp <http://aiohttp.readthedocs.io>`__. In async mode you have all the same properties and methods, but most methods are decorated with an async keyword. If you want to use async mode, you should link against the ``ccxt.async_support`` subpackage, like in the following example:

.. code-block:: Python

   # Python

   import asyncio
   import ccxt.async_support as ccxt

   async def print_poloniex_ethbtc_ticker():
       poloniex = ccxt.poloniex()
       print(await poloniex.fetch_ticker('ETH/BTC'))

   asyncio.run(print_poloniex_ethbtc_ticker())

PHP
^^^

In the PHP 5-compatible version all API methods are synchronous, but with PHP 7.1+ the CCXT library optionally supports asynchronous concurrency mode using the 'yield' syntax (very similar to async/await in Python). The asynchronous PHP version uses the `RecoilPHP <https://github.com/recoilphp/recoil>`__\ , `ReactPHP <https://reactphp.org/>`__ and `clue/reactphp-buzz <https://github.com/clue/reactphp-buzz>`__ libraries. In async mode you have all the same properties and methods, but any networking API method should be decorated with the ``yield`` keyword, your script should be in a ReactPHP/RecoilPHP wrapper, and all exchange constructors need to be passed the loop and kernel instances from the wrapper.

To use the async version of the library, use the ``ccxt_async`` namespace, as in the following example:

.. code-block:: PHP

   // PHP
   <?php
   include 'ccxt.php';

   $loop = \React\EventLoop\Factory::create();
   $kernel = \Recoil\React\ReactKernel::create($loop);
   $kernel->execute(function() use ($loop, $kernel) {
       $poloniex = new \ccxt\async\poloniex(array('loop' => $loop, 'kernel' => $kernel, 'enableRateLimit' => true));
       $result = yield $poloniex->fetch_ticker('ETH/BTC');
       var_dump($result);
   }, $loop);
   $kernel->run();

See further examples in the ``examples/php`` directory; look for filenames that include the ``async`` word. Also, make sure you have installed the required dependencies using ``composer require recoil/recoil clue/buzz-react react/event-loop recoil/react react/http``. Lastly, `this article <https://sergeyzhuk.me/2018/10/26/from-promise-to-coroutines/>`__ provides a good introduction to the methods used here. While syntactically the change is simple (i.e., just using a ``yield`` keyword before relevant methods), concurrency has significant implications for the overall design of your code.

Returned JSON Objects
^^^^^^^^^^^^^^^^^^^^^

All public and private API methods return raw decoded JSON objects in response from the exchanges, as is, untouched. The unified API returns JSON-decoded objects in a common format and structured uniformly across all exchanges.

Passing Parameters To API Methods
---------------------------------

The set of all possible API endpoints differs from exchange to exchange. Most of methods accept a single associative array (or a Python dict) of key-value parameters. The params are passed as follows:

.. code-block:: text

   bitso.publicGetTicker ({ book: 'eth_mxn' })                 // JavaScript
   ccxt.zaif().public_get_ticker_pair ({ 'pair': 'btc_jpy' })  # Python
   $luno->public_get_ticker (array ('pair' => 'XBTIDR'));      // PHP

The unified methods of exchanges might expect and will accept various ``params`` which affect their functionality, like:

.. code-block:: Python

   params = {'type':'margin', 'isIsolated': 'TRUE'}  # --------------┑
   # params will go as the last argument to the unified method       |
   #                                                                 v
   binance.create_order('BTC/USDT', 'limit', 'buy', amount, price, params)

An exchange will not accept the params from a different exchange, they're not interchangeable. The list of accepted parameters is defined by each specific exchange.

To find which parameters can be passed to a unified method:


 * either open the `exchange-specific implementation <https://github.com/ccxt/ccxt/tree/master/js>`__ file and search for the desired function (i.e. ``createOrder``\ ) to inspect and find out the details of ``params`` usage
 * or go to the exchange's API docs and read the list of parameters for your specific function or endpoint (i.e. ``order``\ )

For a full list of accepted method parameters for each exchange, please consult :ref:`API docs <exchanges>`.

API Method Naming Conventions
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

An exchange method name is a concatenated string consisting of type (public or private), HTTP method (GET, POST, PUT, DELETE) and endpoint URL path like in the following examples:

.. list-table::
   :header-rows: 1

   * - Method Name
     - Base API URL
     - Endpoint URL
   * - publicGetIdOrderbook
     - https://bitbay.net/API/Public
     - {id}/orderbook
   * - publicGetPairs
     - https://bitlish.com/api
     - pairs
   * - publicGetJsonMarketTicker
     - https://www.bitmarket.net
     - json/{market}/ticker
   * - privateGetUserMargin
     - https://bitmex.com
     - user/margin
   * - privatePostTrade
     - https://btc-x.is/api
     - trade
   * - tapiCancelOrder
     - https://yobit.net
     - tapi/CancelOrder
   * - ...
     - ...
     - ...


The ccxt library supports both camelcase notation (preferred in JavaScript) and underscore notation (preferred in Python and PHP), therefore all methods can be called in either notation or coding style in any language. Both of these notations work in JavaScript, Python and PHP:

.. code-block:: text

   exchange.methodName ()  // camelcase pseudocode
   exchange.method_name()  // underscore pseudocode

To get a list of all available methods with an exchange instance, you can simply do the following:

.. code-block:: text

   console.log (new ccxt.kraken ())   // JavaScript
   print(dir(ccxt.hitbtc()))           # Python
   var_dump (new \ccxt\okcoinusd ()); // PHP

Unified API
===========



The unified ccxt API is a subset of methods common among the exchanges. It currently contains the following methods:


 * ``fetchMarkets ()``\ : Fetches a list of all available markets from an exchange and returns an array of Market objects as defined by the Market structure (with properties such as ``symbol``\ , ``base``\ , ``quote`` etc.). Some exchanges do not have means for obtaining a list of markets via their online API. For those, the list of markets is hardcoded.
 * ``fetchCurrencies ()``\ : Fetches  all available currencies an exchange and returns an associative dictionary of currencies (objects with properties such as ``code``\ , ``name``\ , etc.). Some exchanges do not have means for obtaining currencies via their online API. For those, the currencies will be extracted from market pairs or hardcoded.
 * ``loadMarkets ([reload])``\ : Returns the list of markets as an object indexed by symbol and caches it with the exchange instance. Returns cached markets if loaded already, unless the ``reload = true`` flag is forced.
 * ``fetchOrderBook (symbol[, limit = undefined[, params = {}]])``\ : Fetch L2/L3 order book for a particular market trading symbol.
 * ``fetchStatus ([, params = {}])``\ : Returns information regarding the exchange status from either the info hardcoded in the exchange instance or the API, if available.
 * ``fetchL2OrderBook (symbol[, limit = undefined[, params]])``\ : Level 2 (price-aggregated) order book for a particular symbol.
 * ``fetchTrades (symbol[, since[, [limit, [params]]]])``\ : Fetch recent trades for a particular trading symbol.
 * ``fetchTicker (symbol)``\ : Fetch latest ticker data by trading symbol.
 * ``fetchBalance ()``\ : Fetch Balance.
 * ``createOrder (symbol, type, side, amount[, price[, params]])``
 * ``createLimitBuyOrder (symbol, amount, price[, params])``
 * ``createLimitSellOrder (symbol, amount, price[, params])``
 * ``createMarketBuyOrder (symbol, amount[, params])``
 * ``createMarketSellOrder (symbol, amount[, params])``
 * ``cancelOrder (id[, symbol[, params]])``
 * ``fetchOrder (id[, symbol[, params]])``
 * ``fetchOrders ([symbol[, since[, limit[, params]]]])``
 * ``fetchOpenOrders ([symbol[, since, limit, params]]]])``
 * ``fetchCanceledOrders ([symbol[, since[, limit[, params]]]])``
 * ``fetchClosedOrders ([symbol[, since[, limit[, params]]]])``
 * ``fetchMyTrades ([symbol[, since[, limit[, params]]]])``
 * ``fetchOpenInterest ([symbol[, params]])``
 * ...

.. code-block:: text

   TODO: ADD LINKS ABOVE

Overriding Unified API Params
-----------------------------

Note, that most of methods of the unified API accept an optional ``params`` argument. It is an associative array (a dictionary, empty by default) containing the params you want to override. The contents of ``params`` are exchange-specific, consult the exchanges' API documentation for supported fields and values. Use the ``params`` dictionary if you need to pass a custom setting or an optional parameter to your unified query.

.. code-block:: JavaScript

   // JavaScript
   (async () => {

       const params = {
           'foo': 'bar',      // exchange-specific overrides in unified queries
           'Hello': 'World!', // see their docs for more details on parameter names
       }

       // the overrides go into the last argument to the unified call ↓ HERE
       const result = await exchange.fetchOrderBook (symbol, length, params)
   }) ()

.. code-block:: Python

   # Python
   params = {
       'foo': 'bar',       # exchange-specific overrides in unified queries
       'Hello': 'World!',  # see their docs for more details on parameter names
   }

   # overrides go in the last argument to the unified call ↓ HERE
   result = exchange.fetch_order_book(symbol, length, params)

.. code-block:: PHP

   // PHP
   $params = array (
       'foo' => 'bar',       // exchange-specific overrides in unified queries
       'Hello' => 'World!',  // see their docs for more details on parameter names
   }

   // overrides go into the last argument to the unified call ↓ HERE
   $result = $exchange->fetch_order_book ($symbol, $length, $params);

Pagination
----------

Most of unified methods will return either a single object or a plain array (a list) of objects (trades, orders, transactions and so on). However, very few exchanges (if any at all) will return all orders, all trades, all ohlcv candles or all transactions at once. Most often their APIs ``limit`` output to a certain number of most recent objects. **YOU CANNOT GET ALL OBJECTS SINCE THE BEGINNING OF TIME TO THE PRESENT MOMENT IN JUST ONE CALL**. Practically, very few exchanges will tolerate or allow that.

To fetch historical orders or trades, the user will need to traverse the data in portions or "pages" of objects. Pagination often implies *"fetching portions of data one by one"* in a loop.

In most cases users are **required to use at least some type of pagination** in order to get the expected results consistently. If the user does not apply any pagination, most methods will return the exchanges' default, which may start from the beginning of history or may be a subset of most recent objects. The default behaviour (without pagination) is exchange-specific! The means of pagination are often used with the following methods in particular:


 * ``fetchTrades()``
 * ``fetchOHLCV()``
 * ``fetchOrders()``
 * ``fetchCanceledOrders()``
 * ``fetchClosedOrder()``
 * ``fetchClosedOrders()``
 * ``fetchOpenOrder()``
 * ``fetchOpenOrders()``
 * ``fetchMyTrades()``
 * ``fetchTransactions()``
 * ``fetchDeposit()``
 * ``fetchDeposits()``
 * ``fetchWithdrawals()``

With methods returning lists of objects, exchanges may offer one or more types of pagination. CCXT unifies **date-based pagination** by default, with timestamps **in milliseconds** throughout the entire library.

Working With Datetimes and Timestamps
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The set of methods for working with UTC dates and timestamps and for converting between them:

.. code-block:: JavaScript

   exchange.parse8601 ('2018-01-01T00:00:00Z') == 1514764800000 // integer, Z = UTC
   exchange.iso8601 (1514764800000) == '2018-01-01T00:00:00Z'   // iso8601 string
   exchange.seconds ()      // integer UTC timestamp in seconds
   exchange.milliseconds () // integer UTC timestamp in milliseconds

Date-based pagination
^^^^^^^^^^^^^^^^^^^^^

This is the type of pagination currently used throughout the CCXT Unified API. The user supplies a ``since`` timestamp **in milliseconds** (!) and a number to ``limit`` results. To traverse the objects of interest page by page, the user runs the following (below is pseudocode, it may require overriding some exchange-specific params, depending on the exchange in question):

.. code-block:: JavaScript

   // JavaScript
   if (exchange.has['fetchTrades']) {
       let since = exchange.milliseconds () - 86400000 // -1 day from now
       // alternatively, fetch from a certain starting datetime
       // let since = exchange.parse8601 ('2018-01-01T00:00:00Z')
       let allTrades = []
       while (since < exchange.milliseconds ()) {
           const symbol = undefined // change for your symbol
           const limit = 20 // change for your limit
           const trades = await exchange.fetchTrades (symbol, since, limit)
           if (trades.length) {
               since = trades[trades.length - 1]['timestamp'] + 1
               allTrades = allTrades.concat (trades)
           } else {
               break
           }
       }
   }

.. code-block:: Python

   # Python
   if exchange.has['fetchOrders']:
       since = exchange.milliseconds () - 86400000  # -1 day from now
       # alternatively, fetch from a certain starting datetime
       # since = exchange.parse8601('2018-01-01T00:00:00Z')
       all_orders = []
       while since < exchange.milliseconds ():
           symbol = None  # change for your symbol
           limit = 20  # change for your limit
           orders = await exchange.fetch_orders(symbol, since, limit)
           if len(orders):
               since = orders[len(orders) - 1]['timestamp'] + 1
               all_orders += orders
           else:
               break

.. code-block:: PHP

   // PHP
   if ($exchange->has['fetchMyTrades']) {
       $since = exchange->milliseconds () - 86400000; // -1 day from now
       // alternatively, fetch from a certain starting datetime
       // $since = $exchange->parse8601 ('2018-01-01T00:00:00Z');
       $all_trades = array ();
       while (since < exchange->milliseconds ()) {
           $symbol = null; // change for your symbol
           $limit = 20; // change for your limit
           $trades = $exchange->fetchMyTrades ($symbol, $since, $limit);
           if (count($trades)) {
               $since = $trades[count($trades) - 1]['timestamp'] + 1;
               $all_trades = array_merge ($all_trades, $trades);
           } else {
               break;
           }
       }
   }

id-based pagination
^^^^^^^^^^^^^^^^^^^

The user supplies a ``from_id`` of the object, from where the query should continue returning results, and a number to ``limit`` results. This is the default with some exchanges, however, this type is not unified (yet). To paginate objects based on their ids, the user would run the following:

.. code-block:: JavaScript

   // JavaScript
   if (exchange.has['fetchTrades']) {
       let from_id = 'abc123' // all ids are strings
       let allTrades = []
       while (true) {
           const symbol = undefined // change for your symbol
           const since = undefined
           const limit = 20 // change for your limit
           const params = {
               'from_id': from_id, // exchange-specific non-unified parameter name
           }
           const trades = await exchange.fetchTrades (symbol, since, limit, params)
           if (trades.length) {
               from_id = trades[trades.length - 1]['id']
               allTrades.push (trades)
           } else {
               break
           }
       }
   }

.. code-block:: Python

   # Python
   if exchange.has['fetchOrders']:
       from_id = 'abc123'  # all ids are strings
       all_orders = []
       while True:
           symbol = None  # change for your symbol
           since = None
           limit = 20  # change for your limit
           params = {
               'from_id': from_id,  # exchange-specific non-unified parameter name
           }
           orders = await exchange.fetch_orders(symbol, since, limit, params)
           if len(orders):
               from_id = orders[len(orders) - 1]['id']
               all_orders += orders
           else:
               break

.. code-block:: PHP

   // PHP
   if ($exchange->has['fetchMyTrades']) {
       $from_id = 'abc123' // all ids are strings
       $all_trades = array ();
       while (true) {
           $symbol = null; // change for your symbol
           $since = null;
           $limit = 20; // change for your limit
           $params = array (
               'from_id' => $from_id, // exchange-specific non-unified parameter name
           );
           $trades = $exchange->fetchMyTrades ($symbol, $since, $limit, $params);
           if (count($trades)) {
               $from_id = $trades[count($trades) - 1]['id'];
               $all_trades = array_merge ($all_trades, $trades);
           } else {
               break;
           }
       }
   }

Pagenumber-based (cursor) pagination
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The user supplies a page number or an *initial "cursor"* value. The exchange returns a page of results and the *next "cursor"* value, to proceed from. Most of exchanges that implement this type of pagination will either return the next cursor within the response itself or will return the next cursor values within HTTP response headers.

See an example implementation here: https://github.com/ccxt/ccxt/blob/master/examples/py/coinbasepro-fetch-my-trades-pagination.py

Upon each iteration of the loop the user has to take the next cursor and put it into the overrided params for the next query (on the following iteration):

.. code-block:: JavaScript

   // JavaScript
   if (exchange.has['fetchTrades']) {
       let page = 0  // exchange-specific type and value
       let allTrades = []
       while (true) {
           const symbol = undefined // change for your symbol
           const since = undefined
           const limit = 20 // change for your limit
           const params = {
               'page': page, // exchange-specific non-unified parameter name
           }
           const trades = await exchange.fetchTrades (symbol, since, limit, params)
           if (trades.length) {
               // not thread-safu and exchange-specific !
               page = exchange.last_json_response['cursor']
               allTrades.push (trades)
           } else {
               break
           }
       }
   }

.. code-block:: Python

   # Python
   if exchange.has['fetchOrders']:
       cursor = 0  # exchange-specific type and value
       all_orders = []
       while True:
           symbol = None  # change for your symbol
           since = None
           limit = 20  # change for your limit
           params = {
               'cursor': cursor,  # exchange-specific non-unified parameter name
           }
           orders = await exchange.fetch_orders(symbol, since, limit, params)
           if len(orders):
               # not thread-safu and exchange-specific !
               cursor = exchange.last_response_headers['CB-AFTER']
               all_orders += orders
           else:
               break

.. code-block:: PHP

   // PHP
   if ($exchange->has['fetchMyTrades']) {
       $start = '0' // exchange-specific type and value
       $all_trades = array ();
       while (true) {
           $symbol = null; // change for your symbol
           $since = null;
           $limit = 20; // change for your limit
           $params = array (
               'start' => $start, // exchange-specific non-unified parameter name
           );
           $trades = $exchange->fetchMyTrades ($symbol, $since, $limit, $params);
           if (count($trades)) {
               // not thread-safu and exchange-specific !
               $start = $exchange->last_json_response['next'];
               $all_trades = array_merge ($all_trades, $trades);
           } else {
               break;
           }
       }
   }

Public API
==========



Order Book
----------

Exchanges expose information on open orders with bid (buy) and ask (sell) prices, volumes and other data. Usually there is a separate endpoint for querying current state (stack frame) of the *order book* for a particular market. An order book is also often called *market depth*. The order book information is used in the trading decision making process.

To get data on order books, you can use


 * ``fetchOrderBook ()`` // for a single markets order books
 * ``fetchOrderBooks ( symbols )`` // for multiple markets order books
 * ``fetchOrderBooks ()`` // for the order books of all markets

.. code-block:: JavaScript

   async fetchOrderBook (symbol, limit = undefined, params = {})

Parameters


 * **symbol** (String) *required* Unified CCXT symbol (e.g. ``"BTC/USDT"``\ )
 * **limit** (Integer) The number of orders to return in the order book (e.g. ``10``\ )
 * **params** (Dictionary) Extra parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * An :ref:`order book structure <order book structure>`

.. code-block:: JavaScript

   async fetchOrderBooks (symbols = undefined, limit = undefined, params = {})

Parameters


 * **symbols** ([String]) Unified CCXT symbols (e.g. ``["BTC/USDT", "ETH/USDT"]``\ )
 * **limit** (Integer) The number of orders to return in the order book (e.g. ``10``\ )
 * **params** (Dictionary) Extra parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * A dictionary of :ref:`order book structures <order book structure>` indexed by market symbols

fetchOrderBook Examples
^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   // JavaScript
   delay = 2000 // milliseconds = seconds * 1000
   (async () => {
       for (symbol in exchange.markets) {
           console.log (await exchange.fetchOrderBook (symbol))
           await new Promise (resolve => setTimeout (resolve, delay)) // rate limit
       }
   }) ()

.. code-block:: Python

   # Python
   import time
   delay = 2 # seconds
   for symbol in exchange.markets:
       print (exchange.fetch_order_book (symbol))
       time.sleep (delay) # rate limit

.. code-block:: PHP

   // PHP
   $delay = 2000000; // microseconds = seconds * 1000000
   foreach ($exchange->markets as $symbol => $market) {
       var_dump ($exchange->fetch_order_book ($symbol));
       usleep ($delay); // rate limit
   }

Order Book Structure
^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   {
       'bids': [
           [ price, amount ], // [ float, float ]
           [ price, amount ],
           ...
       ],
       'asks': [
           [ price, amount ],
           [ price, amount ],
           ...
       ],
       'symbol': 'ETH/BTC', // a unified market symbol
       'timestamp': 1499280391811, // Unix Timestamp in milliseconds (seconds * 1000)
       'datetime': '2017-07-05T18:47:14.692Z', // ISO8601 datetime string with milliseconds
       'nonce': 1499280391811, // an increasing unique identifier of the orderbook snapshot
   }

 **The timestamp and datetime may be missing (\ ``undefined/None/null``\ ) if the exchange in question does not provide a corresponding value in the API response.**

Prices and amounts are floats. The bids array is sorted by price in descending order. The best (highest) bid price is the first element and the worst (lowest) bid price is the last element. The asks array is sorted by price in ascending order. The best (lowest) ask price is the first element and the worst (highest) ask price is the last element. Bid/ask arrays can be empty if there are no corresponding orders in the order book of an exchange.

Exchanges may return the stack of orders in various levels of details for analysis. It is either in full detail containing each and every order, or it is aggregated having slightly less detail where orders are grouped and merged by price and volume. Having greater detail requires more traffic and bandwidth and is slower in general but gives a benefit of higher precision. Having less detail is usually faster, but may not be  enough in some very specific cases.

Notes On Order Book Structure
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


 * The ``orderbook['timestamp']`` is the time when the exchange generated this orderbook response (before replying it back to you). This may be missing (\ ``undefined/None/null``\ ), as documented in the Manual, not all exchanges provide a timestamp there. If it is defined, then it is the UTC timestamp **in milliseconds** since 1 Jan 1970 00:00:00.
 * Some exchanges may index orders in the orderbook by order ids, in that case the order id may be returned as the third element of bids and asks: ``[ price, amount, id ]``. This is often the case with L3 orderbooks without aggregation. The order ``id``\ , if shown in the orderbook, refers to the orderbook and does not necessarily correspond to the actual order id from the exchanges' database as seen by the owner or by the others. The order id is an ``id`` of the row inside the orderbook, but not necessarily the true-\ ``id`` of the order (though, they may be equal as well, depending on the exchange in question).
 * In some cases the exchanges may supply L2 aggregated orderbooks with order counts for each aggregated level, in that case the order count may be returned as the third element of bids and asks: ``[ price, amount, count ]``. The ``count`` tells how many orders are aggregated on each price level in bids and asks.
 * Also, some exchanges may return the order timestamp as the third element of bids and asks: ``[ price, amount, timestamp ]``. The ``timestamp`` tells when the order was placed on the orderbook.

Market Depth
^^^^^^^^^^^^

Some exchanges accept a dictionary of extra parameters to the ``fetchOrderBook () / fetch_order_book ()`` function. *\ *All extra ``params`` are exchange-specific (non-unified). You will need to consult exchanges docs if you want to override a particular param, like the depth of the order book. You can get a limited count of returned orders or a desired level of aggregation (aka *\ market depth*) by specifying an limit argument and exchange-specific extra ``params`` like so:

.. code-block:: JavaScript

   // JavaScript

   (async function test () {
       const ccxt = require ('ccxt')
       const exchange = new ccxt.bitfinex ()
       const limit = 5
       const orders = await exchange.fetchOrderBook ('BTC/USD', limit, {
           // this parameter is exchange-specific, all extra params have unique names per exchange
           'group': 1, // 1 = orders are grouped by price, 0 = orders are separate
       })
   }) ()

.. code-block:: Python

   # Python

   import ccxt
   # return up to ten bidasks on each side of the order book stack
   limit = 10
   ccxt.cex().fetch_order_book('BTC/USD', limit)

.. code-block:: PHP

   // PHP

   // instantiate the exchange by id
   $exchange = '\\ccxt\\kraken';
   $exchange = new $exchange ();
   // up to ten orders on each side, for example
   $limit = 20;
   var_dump ($exchange->fetch_order_book ('BTC/USD', $limit));

The levels of detail or levels of order book aggregation are often number-labelled like L1, L2, L3...


 * **L1**\ : less detail for quickly obtaining very basic info, namely, the market price only. It appears to look like just one order in the order book.
 * **L2**\ : most common level of aggregation where order volumes are grouped by price. If two orders have the same price, they appear as one single order for a volume equal to their total sum. This is most likely the level of aggregation you need for the majority of purposes.
 * **L3**\ : most detailed level with no aggregation where each order is separate from other orders. This LOD naturally contains duplicates in the output. So, if two orders have equal prices they are **not** merged together and it's up to the exchange's matching engine to decide on their priority in the stack. You don't really need L3 detail for successful trading. In fact, you most probably don't need it at all. Therefore some exchanges don't support it and always return aggregated order books.

If you want to get an L2 order book, whatever the exchange returns, use the ``fetchL2OrderBook(symbol, limit, params)`` or ``fetch_l2_order_book(symbol, limit, params)`` unified method for that.

The ``limit`` argument does not guarantee that the number of bids or asks will always be equal to ``limit``. It designates the upper boundary or the maximum, so at some moment in time there may be less than ``limit`` bids or asks. This is the case when the exchange does not have enough orders on the orderbook. However, if the underlying exchange API does not support a ``limit`` parameter for the orderbook endpoint at all, then the ``limit`` argument will be ignored. CCXT does not trim ``bids`` and ``asks`` if the exchange returns more than you request.

Market Price
^^^^^^^^^^^^

In order to get current best price (query market price) and calculate bidask spread take first elements from bid and ask, like so:

.. code-block:: JavaScript

   // JavaScript
   let orderbook = await exchange.fetchOrderBook (exchange.symbols[0])
   let bid = orderbook.bids.length ? orderbook.bids[0][0] : undefined
   let ask = orderbook.asks.length ? orderbook.asks[0][0] : undefined
   let spread = (bid && ask) ? ask - bid : undefined
   console.log (exchange.id, 'market price', { bid, ask, spread })

.. code-block:: Python

   # Python
   orderbook = exchange.fetch_order_book (exchange.symbols[0])
   bid = orderbook['bids'][0][0] if len (orderbook['bids']) > 0 else None
   ask = orderbook['asks'][0][0] if len (orderbook['asks']) > 0 else None
   spread = (ask - bid) if (bid and ask) else None
   print (exchange.id, 'market price', { 'bid': bid, 'ask': ask, 'spread': spread })

.. code-block:: PHP

   // PHP
   $orderbook = $exchange->fetch_order_book ($exchange->symbols[0]);
   $bid = count ($orderbook['bids']) ? $orderbook['bids'][0][0] : null;
   $ask = count ($orderbook['asks']) ? $orderbook['asks'][0][0] : null;
   $spread = ($bid && $ask) ? $ask - $bid : null;
   $result = array ('bid' => $bid, 'ask' => $ask, 'spread' => $spread);
   var_dump ($exchange->id, 'market price', $result);

Price Tickers
-------------

A price ticker contains statistics for a particular market/symbol for some period of time in recent past, usually last 24 hours. The methods for fetching tickers are described below.

A Single Ticker For One Symbol
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   // one ticker
   fetchTicker (symbol, params = {})

   // example
   fetchTicker ('ETH/BTC')
   fetchTicker ('BTC/USDT')

Multiple Tickers For All Or Many Symbols
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   // multiple tickers
   fetchTickers (symbols = undefined, params = {})  // for all tickers at once

   // for example
   fetchTickers () // all symbols
   fetchTickers ([ 'ETH/BTC', 'BTC/USDT' ]) // an array of specific symbols

Check the ``exchange.has['fetchTicker']`` and ``exchange.has['fetchTickers']`` properties of the exchange instance to determine if the exchange in question does support these methods.

 **Please, note, that calling ``fetchTickers ()`` without a symbol is usually strictly rate-limited, an exchange may ban you if you poll that endpoint too frequently.**

Ticker structure
^^^^^^^^^^^^^^^^

A ticker is a statistical calculation with the information calculated over the past 24 hours for a specific market.

The structure of a ticker is as follows:

.. code-block:: JavaScript

   {
       'symbol':        string symbol of the market ('BTC/USD', 'ETH/BTC', ...)
       'info':        { the original non-modified unparsed reply from exchange API },
       'timestamp':     int (64-bit Unix Timestamp in milliseconds since Epoch 1 Jan 1970)
       'datetime':      ISO8601 datetime string with milliseconds
       'high':          float, // highest price
       'low':           float, // lowest price
       'bid':           float, // current best bid (buy) price
       'bidVolume':     float, // current best bid (buy) amount (may be missing or undefined)
       'ask':           float, // current best ask (sell) price
       'askVolume':     float, // current best ask (sell) amount (may be missing or undefined)
       'vwap':          float, // volume weighed average price
       'open':          float, // opening price
       'close':         float, // price of last trade (closing price for current period)
       'last':          float, // same as `close`, duplicated for convenience
       'previousClose': float, // closing price for the previous period
       'change':        float, // absolute change, `last - open`
       'percentage':    float, // relative change, `(change/open) * 100`
       'average':       float, // average price, `(last + open) / 2`
       'baseVolume':    float, // volume of base currency traded for last 24 hours
       'quoteVolume':   float, // volume of quote currency traded for last 24 hours
   }

Notes On Ticker Structure
^^^^^^^^^^^^^^^^^^^^^^^^^


 * All fields in the ticker represent the past 24 hours prior to ``timestamp``.
 * The ``bidVolume`` is the volume (amount) of current best bid in the orderbook.
 * The ``askVolume`` is the volume (amount) of current best ask in the orderbook.
 * The ``baseVolume`` is the amount of base currency traded (bought or sold) in last 24 hours.
 * The ``quoteVolume`` is the amount of quote currency traded (bought or sold) in last 24 hours.

 **All prices in ticker structure are in quote currency. Some fields in a returned ticker structure may be undefined/None/null.**

.. code-block:: text

   base currency ↓
                BTC / USDT
                ETH / BTC
               DASH / ETH
                       ↑ quote currency

Timestamp and datetime are both Universal Time Coordinated (UTC) in milliseconds.


 * ``ticker['timestamp']`` is the time when the exchange generated this response (before replying it back to you). It may be missing (\ ``undefined/None/null``\ ), as documented in the Manual, not all exchanges provide a timestamp there. If it is defined, then it is a UTC timestamp **in milliseconds** since 1 Jan 1970 00:00:00.
 * ``exchange.last_response_headers['Date']`` is the date-time string of the last HTTP response received (from HTTP headers). The 'Date' parser should respect the timezone designated there. The precision of the date-time is 1 second, 1000 milliseconds. This date should be set by the exchange server when the message originated according to the following standards:

  * https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.18
  * https://tools.ietf.org/html/rfc1123#section-5.2.14
  * https://tools.ietf.org/html/rfc822#section-5

Although some exchanges do mix-in orderbook's top bid/ask prices into their tickers (and some exchanges even serve top bid/ask volumes) you should not treat a ticker as a ``fetchOrderBook`` replacement. The main purpose of a ticker is to serve statistical data, as such, treat it as "live 24h OHLCV". It is known that exchanges discourage frequent ``fetchTicker`` requests by imposing stricter rate limits on these queries. If you need a unified way to access bids and asks you should use ``fetchL[123]OrderBook`` family instead.

To get historical prices and volumes use the unified :ref:`\ ``fetchOHLCV`` <ohlcv candlestick charts>` method where available. To get historical mark, index, and premium index prices, add one of ``'price': 'mark'``\ , ``'price': 'index'``\ , ``'price': 'premiumIndex'`` respectively to the :ref:`params-overrides <overriding unified api params>` of ``fetchOHLCV``. There are also convenience methods ``fetchMarkPriceOHLCV``\ , ``fetchIndexPriceOHLCV``\ , and ``fetchPremiumIndexOHLCV`` that obtain the mark, index and premiumIndex historical prices and volumes.

Methods for fetching tickers:


 * ``fetchTicker (symbol[, params = {}])``\ , symbol is required, params are optional
 * ``fetchTickers ([symbols = undefined[, params = {}]])``\ , both arguments optional

Individually By Symbol
^^^^^^^^^^^^^^^^^^^^^^

To get the individual ticker data from an exchange for a particular trading pair or a specific symbol – call the ``fetchTicker (symbol)``\ :

.. code-block:: JavaScript

   // JavaScript
   if (exchange.has['fetchTicker']) {
       console.log (await (exchange.fetchTicker ('BTC/USD'))) // ticker for BTC/USD
       let symbols = Object.keys (exchange.markets)
       let random = Math.floor (Math.random () * (symbols.length - 1))
       console.log (exchange.fetchTicker (symbols[random])) // ticker for a random symbol
   }

.. code-block:: Python

   # Python
   import random
   if (exchange.has['fetchTicker']):
       print(exchange.fetch_ticker('LTC/ZEC')) # ticker for LTC/ZEC
       symbols = list(exchange.markets.keys())
       print(exchange.fetch_ticker(random.choice(symbols))) # ticker for a random symbol

.. code-block:: PHP

   // PHP (don't forget to set your timezone properly!)
   if ($exchange->has['fetchTicker']) {
       var_dump ($exchange->fetch_ticker ('ETH/CNY')); // ticker for ETH/CNY
       $symbols = array_keys ($exchange->markets);
       $random = rand () % count ($symbols);
       var_dump ($exchange->fetch_ticker ($symbols[$random])); // ticker for a random symbol
   }

All At Once
^^^^^^^^^^^

Some exchanges (not all of them) also support fetching all tickers at once. See :ref:`their docs <exchanges>` for details. You can fetch all tickers with a single call like so:

.. code-block:: JavaScript

   // JavaScript
   if (exchange.has['fetchTickers']) {
       console.log (await (exchange.fetchTickers ())) // all tickers indexed by their symbols
   }

.. code-block:: Python

   # Python
   if (exchange.has['fetchTickers']):
       print(exchange.fetch_tickers()) # all tickers indexed by their symbols

.. code-block:: PHP

   // PHP
   if ($exchange->has['fetchTickers']) {
       var_dump ($exchange->fetch_tickers ()); // all tickers indexed by their symbols
   }

Fetching all tickers requires more traffic than fetching a single ticker. Also, note that some exchanges impose higher rate-limits on subsequent fetches of all tickers (see their docs on corresponding endpoints for details). **The cost of the ``fetchTickers()`` call in terms of rate limit is often higher than average**. If you only need one ticker, fetching by a particular symbol is faster as well. You probably want to fetch all tickers only if you really need all of them and, most likely, you don't want to fetchTickers more frequently than once in a minute or so.

Also, some exchanges may impose additional requirements on the ``fetchTickers()`` call, sometimes you can't fetch the tickers for all symbols because of the API limitations of the exchange in question. Some exchanges accept a list of symbols in HTTP URL query params, however, because URL length is limited, and in extreme cases exchanges can have thousands of markets – a list of all their symbols simply would not fit in the URL, so it has to be a limited subset of their symbols. Sometimes, there are other reasons for requiring a list of symbols, and there may be a limit on the number of symbols you can fetch at once, but whatever the limitation, please, blame the exchange. To pass the symbols of interest to the exchange, you can supply a list of strings as the first argument to fetchTickers:

.. code-block:: JavaScript

   //JavaScript
   if (exchange.has['fetchTickers']) {
       console.log (await (exchange.fetchTickers ([ 'ETH/BTC', 'LTC/BTC' ]))) // listed tickers indexed by their symbols
   }

.. code-block:: Python

   # Python
   if (exchange.has['fetchTickers']):
       print(exchange.fetch_tickers(['ETH/BTC', 'LTC/BTC'])) # listed tickers indexed by their symbols

.. code-block:: PHP

   // PHP
   if ($exchange->has['fetchTickers']) {
       var_dump ($exchange->fetch_tickers (array ('ETH/BTC', 'LTC/BTC'))); // listed tickers indexed by their symbols
   }

Note that the list of symbols is not required in most cases, but you must add additional logic if you want to handle all possible limitations that might be imposed on the exchanges' side.

Like most methods of the Unified CCXT API, the last argument to fetchTickers is the ``params`` argument for overriding request parameters that are sent towards the exchange.

The structure of the returned value is as follows:

.. code-block:: JavaScript

   {
       'info':    { ... }, // the original JSON response from the exchange as is
       'BTC/USD': { ... }, // a single ticker for BTC/USD
       'ETH/BTC': { ... }, // a ticker for ETH/BTC
       ...
   }

A general solution for fetching all tickers from all exchanges (even the ones that don't have a corresponding API endpoint) is on the way, this section will be updated soon.

.. code-block:: text

   UNDER CONSTRUCTION

OHLCV Candlestick Charts
------------------------

.. code-block:: diff

   - this is under heavy development right now, contributions appreciated

Most exchanges have endpoints for fetching OHLCV data, but some of them don't. The exchange boolean (true/false) property named ``has['fetchOHLCV']`` indicates whether the exchange supports candlestick data series or not.

The ``fetchOHLCV`` method is declared in the following way:

.. code-block:: JavaScript

   fetchOHLCV (symbol, timeframe = '1m', since = undefined, limit = undefined, params = {})

You can call the unified ``fetchOHLCV`` / ``fetch_ohlcv`` method to get the list of OHLCV candles for a particular symbol like so:

.. code-block:: JavaScript

   // JavaScript
   let sleep = (ms) => new Promise (resolve => setTimeout (resolve, ms));
   if (exchange.has.fetchOHLCV) {
       for (symbol in exchange.markets) {
           await sleep (exchange.rateLimit) // milliseconds
           console.log (await exchange.fetchOHLCV (symbol, '1m')) // one minute
       }
   }

.. code-block:: Python

   # Python
   import time
   if exchange.has['fetchOHLCV']:
       for symbol in exchange.markets:
           time.sleep (exchange.rateLimit / 1000) # time.sleep wants seconds
           print (symbol, exchange.fetch_ohlcv (symbol, '1d')) # one day

.. code-block:: PHP

   // PHP
   if ($exchange->has['fetchOHLCV']) {
       foreach ($exchange->markets as $symbol => $market) {
           usleep ($exchange->rateLimit * 1000); // usleep wants microseconds
           var_dump ($exchange->fetch_ohlcv ($symbol, '1M')); // one month
       }
   }

To get the list of available timeframes for your exchange see the ``timeframes`` property. Note that it is only populated when ``has['fetchOHLCV']`` is true as well.

The returned list of candles may have one or more missing periods, if the exchange did not have any trades for the specified timerange and symbol. To a user that would appear as gaps in a continuous list of candles. That is considered normal. If the exchange did not have any candles at that time, the CCXT library will show the results as returned from the exchange itself.

 **There's a limit on how far back in time your requests can go.** Most of exchanges will not allow to query detailed candlestick history (like those for 1-minute and 5-minute timeframes) too far in the past. They usually keep a reasonable amount of most recent candles, like 1000 last candles for any timeframe is more than enough for most of needs. You can work around that limitation by continuously fetching (aka *REST polling*\ ) latest OHLCVs and storing them in a CSV file or in a database.

 **Note that the info from the last (current) candle may be incomplete until the candle is closed (until the next candle starts).**

Like with most other unified and implicit methods, the ``fetchOHLCV`` method accepts as its last argument an associative array (a dictionary) of extra ``params``\ , which is used to :ref:`override default values <overriding unified api params>` that are sent in requests to the exchanges. The contents of ``params`` are exchange-specific, consult the exchanges' API documentation for supported fields and values.

The ``since`` argument is an integer UTC timestamp **in milliseconds** (everywhere throughout the library with all unified methods).

If ``since`` is not specified the ``fetchOHLCV`` method will return the time range as is the default from the exchange itself.  This is not a bug. Some exchanges will return candles from the beginning of time, others will return most recent candles only, the exchanges' default behaviour is expected. Thus, without specifying ``since`` the range of returned candles will be exchange-specific. One should pass  the ``since`` argument to ensure getting precisely the history range needed.

Notes On Latency
^^^^^^^^^^^^^^^^

Trading strategies require fresh up-to-date information for technical analysis, indicators and signals. Building a speculative trading strategy based on the OHLCV candles received from the exchange may have critical drawbacks. Developers should account for the details explained in this section to build successful bots.

First and foremost, when using CCXT you're talking to the exchanges directly. CCXT is not a server, nor a service, it's a software library. All data that you are getting with CCXT is received directly from the exchanges first-hand.

The exchanges usually provide two categories of public market data:


#. Fast primary first-order data that includes real time orderbooks and trades or fills
#. Slow second-order data that includes secondary tickers and kline OHLCV candles, that are calculated from the first-order data

The primary first-order data is updated by the exchanges APIs in pseudo real time, or as close to real time as possible, as fast as possible. The second-order data requires time for the exchange to calculate it. For example, a ticker is nothing more than a rolling 24-hour statistical cut of orderbooks and trades. OHLCV candles and volumes are also calculated from first-order trades and represent fixed statistical cuts of specific periods. The volume traded within an hour is just a sum of traded volumes of the corresponding trades that happened within that hour.

Obviously, it takes some time for the exchange to collect the first-order data and calculate the secondary statistical data from it. That literally means that **tickers and OHLCVs are always slower than orderbooks and trades**. In other words, there is always some latency in the exchange API between the moment when a trade happens and the moment when a corresponding OHLCV candle is updated or published by the exchange API.

The latency (or how much time is needed by the exchange API for calculating the secondary data) depends on how fast the exchange engine is, so it is exchange-specific. Top exchange engines will usually return and update fresh last-minute OHLCV candles and tickers at a very fast rate. Some exchanges might do it in regular intervals like once a second or once in a few seconds. Slow exchange engines might take minutes to update the secondary statistical information, their APIs might return the current most recent OHLCV candle a few minutes late.

If your strategy depends on the fresh last-minute most recent data you don't want to build it based on tickers or OHLCVs received from the exchange. Tickers and exchanges' OHLCVs are only suitable for display purposes, or for simple trading strategies for hour-timeframes or day-timeframes that are less susceptible to latency.

Thankfully, the developers of time-critical trading strategies don't have to rely on secondary data from the exchanges and can calculate the OHLCVs and tickers in the userland. That may be faster and more efficient than waiting for the exchanges to update the info on their end. One can aggregate the public trade history by polling it frequently and calculate candles by walking over the list of trades. CCXT offers a ``buildOHLCVC/build_ohlcvc`` base method for that:


 * JavaScript: https://github.com/ccxt/ccxt/blob/master/js/base/functions/misc.js#L43
 * Python: https://github.com/ccxt/ccxt/blob/master/python/ccxt/base/exchange.py#L1933
 * PHP: https://github.com/ccxt/ccxt/blob/master/php/Exchange.php#L631

Due to the differences in their internal implementations the exchanges may be faster to update their primary and secondary market data over WebSockets (see https://ccxt.pro). The latency remains exchange-specific, cause the exchange engine still needs time to calculate the secondary data, regardless of whether you're polling it over the RESTful API with CCXT or getting updates via WebSockets with CCXT Pro. WebSockets can improve the networking latency, so a fast exchange will work even better, but adding the support for WS subscriptions will not make a slow exchange engine work much faster.

If you want to stay on top of the second-order data latency, then you will have to calculate it on your side and beat the exchange engine in speed of doing so. Depending on the needs of your application, it may be tricky, since you will need to handle redundancy, "data holes" in the history, exchange downtimes, and other aspects of data aggregation which is a whole universe in itself that is impossible to fully cover in this Manual.

OHLCV Structure
^^^^^^^^^^^^^^^

The fetchOHLCV method shown above returns a list (a flat array) of OHLCV candles represented by the following structure:

.. code-block:: JavaScript

   [
       [
           1504541580000, // UTC timestamp in milliseconds, integer
           4235.4,        // (O)pen price, float
           4240.6,        // (H)ighest price, float
           4230.0,        // (L)owest price, float
           4230.7,        // (C)losing price, float
           37.72941911    // (V)olume float (usually in terms of the base currency, the exchanges docstring may list whether quote or base units are used)
       ],
       ...
   ]

The list of candles is returned sorted in ascending (historical/chronological) order, oldest candle first, most recent candle last.

Mark, Index and PremiumIndex Candlestick Charts
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

To obtain historical Mark, Index Price and Premium Index candlesticks pass the ``'price'`` :doc:`params-override <overriding unified api params>` to ``fetchOHLCV``. The ``'price'`` parameter accepts one of the following values:


 * ``'mark'``
 * ``'index'``
 * ``'premiumIndex'``

.. code-block:: JavaScript

   // JavaScript
   async function main () {
       const exchange = new ccxt.binanceusdm ()
       const markKlines = await exchange.fetchOHLCV ('ADA/USDT', '1h', undefined, undefined, { 'price': 'mark' })
       console.log (markKlines)
       const indexKlines = await exchange.fetchOHLCV ('ADA/USDT', '1h', undefined, undefined, { 'price': 'index' })
       console.log (indexKlines)
   }

   main ()

There are also convenience methods ``fetchMarkOHLCV``\ , ``fetchIndexOHLCV`` and ``fetchPremiumIndexOHLCV``

.. code-block:: JavaScript

   // JavaScript
   async function main () {
       const exchange = new ccxt.binanceusdm ()
       const markKlines = await exchange.fetchMarkOHLCV ('ADA/USDT', '1h')
       console.log (markKlines)
       const indexKlines = await exchange.fetchIndexOHLCV ('ADA/USDT', '1h')
       console.log (indexKlines)
   }

   main ()

.. code-block:: Python

   # Python
   exchange = ccxt.binance()
   response = exchange.fetch_ohlcv('ADA/USDT', '1h', params={'price':'index'})
   pprint(response)
   # Convenience methods
   mark_klines = exchange.fetch_mark_ohlcv('ADA/USDT', '1h')
   index_klines = exchange.fetch_index_ohlcv('ADA/USDT', '1h')
   pprint(mark_klines)
   pprint(index_klines)

OHLCV Emulation
^^^^^^^^^^^^^^^

Some exchanges don't offer any OHLCV method, and for those, the ccxt library will emulate OHLCV candles from :ref:`Public Trades <public trades>`. In that case you will see ``exchange.has['fetchOHLCV'] = 'emulated'``. However, because the trade history is usually very limited, the emulated fetchOHLCV methods cover most recent info only and should only be used as a fallback, when no other option is available.

 **WARNING: the fetchOHLCV emulation is experimental!**

.. code-block:: text

   UNDER CONSTRUCTION

Public Trades
-------------

.. code-block:: diff

   - this is under heavy development right now, contributions appreciated

You can call the unified ``fetchTrades`` / ``fetch_trades`` method to get the list of most recent trades for a particular symbol. The ``fetchTrades`` method is declared in the following way:

.. code-block:: JavaScript

   async fetchTrades (symbol, since = undefined, limit = undefined, params = {})

For example, if you want to print recent trades for all symbols one by one sequentially (mind the rateLimit!) you would do it like so:

.. code-block:: JavaScript

   // JavaScript
   if (exchange.has['fetchTrades']) {
       let sleep = (ms) => new Promise (resolve => setTimeout (resolve, ms));
       for (symbol in exchange.markets) {
           console.log (await exchange.fetchTrades (symbol))
       }
   }

.. code-block:: Python

   # Python
   import time
   if exchange.has['fetchTrades']:
       for symbol in exchange.markets:  # ensure you have called loadMarkets() or load_markets() method.
           print (symbol, exchange.fetch_trades (symbol))

.. code-block:: PHP

   // PHP
   if ($exchange->has['fetchTrades']) {
       foreach ($exchange->markets as $symbol => $market) {
           var_dump ($exchange->fetch_trades ($symbol));
       }
   }

The fetchTrades method shown above returns an ordered list of trades (a flat array, sorted by timestamp in ascending order, oldest trade first, most recent trade last). A list of trades is represented by the following structure:

.. code-block:: JavaScript

   [
       {
           'info':       { ... },                  // the original decoded JSON as is
           'id':        '12345-67890:09876/54321', // string trade id
           'timestamp':  1502962946216,            // Unix timestamp in milliseconds
           'datetime':  '2017-08-17 12:42:48.000', // ISO8601 datetime with milliseconds
           'symbol':    'ETH/BTC',                 // symbol
           'order':     '12345-67890:09876/54321', // string order id or undefined/None/null
           'type':      'limit',                   // order type, 'market', 'limit' or undefined/None/null
           'side':      'buy',                     // direction of the trade, 'buy' or 'sell'
           'price':      0.06917684,               // float price in quote currency
           'amount':     1.5,                      // amount of base currency
       },
       ...
   ]

Most exchanges return most of the above fields for each trade, though there are exchanges that don't return the type, the side, the trade id or the order id of the trade. Most of the time you are guaranteed to have the timestamp, the datetime, the symbol, the price and the amount of each trade.

The second optional argument ``since`` reduces the array by timestamp, the third ``limit`` argument reduces by number (count) of returned items.

If the user does not specify ``since``\ , the ``fetchTrades`` method will return the default range of public trades from the exchange. The default set is exchange-specific, some exchanges will return trades starting from the date of listing a pair on the exchange, other exchanges will return a reduced set of trades (like, last 24 hours, last 100 trades, etc). If the user wants precise control over the timeframe, the user is responsible for specifying the ``since`` argument.

Most of unified methods will return either a single object or a plain array (a list) of objects (trades). However, very few exchanges (if any at all) will return all trades at once. Most often their APIs ``limit`` output to a certain number of most recent objects. **YOU CANNOT GET ALL OBJECTS SINCE THE BEGINNING OF TIME TO THE PRESENT MOMENT IN JUST ONE CALL**. Practically, very few exchanges will tolerate or allow that.

To fetch historical trades, the user will need to traverse the data in portions or "pages" of objects. Pagination often implies *"fetching portions of data one by one"* in a loop.

In most cases users are **required to use at least some type of pagination** in order to get the expected results consistently.

On the other hand, **some exchanges don't support pagination for public trades at all**. In general the exchanges will provide just the most recent trades.

The ``fetchTrades ()`` / ``fetch_trades()`` method also accepts an optional ``params`` (assoc-key array/dict, empty by default) as its fourth argument. You can use it to pass extra params to method calls or to override a particular default value (where supported by the exchange). See the API docs for your exchange for more details.

Exchange Time
-------------

The ``fetchTime()`` method (if available) returns the current integer timestamp in milliseconds from the exchange server.

.. code-block:: JavaScript

   fetchTime(params = {})

Exchange Status
---------------

The exchange status describes the latest known information on the availability of the exchange API. This information is either hardcoded into the exchange class or fetched live directly from the exchange API. The ``fetchStatus(params = {})`` method can be used to get this information. The status returned by ``fetchStatus`` is one of:


 * Hardcoded into the exchange class, e.g. if the API has been broken or shutdown.
 * Updated using the exchange ping or ``fetchTime`` endpoint to see if its alive
 * Updated using the dedicated exchange API status endpoint.

.. code-block:: Javascript

   fetchStatus(params = {})

Exchange Status Structure
^^^^^^^^^^^^^^^^^^^^^^^^^

The ``fetchStatus()`` method will return a status structure like shown below:

.. code-block:: Javascript

   {
       'status': 'ok', // 'ok', 'shutdown', 'error', 'maintenance'
       'updated': undefined, // integer, last updated timestamp in milliseconds if updated via the API
       'eta': undefined, // when the maintenance or outage is expected to end
       'url': undefined, // a link to a GitHub issue or to an exchange post on the subject
       'info': { ... }
   }

The possible values in the ``status`` field are:


 * ``'ok'`` means the exchange API is fully operational
 * ``'shutdown``\ ' means the exchange was closed, and the ``updated`` field should contain the datetime of the shutdown
 * ``'error'`` means that either the exchange API is broken, or the implementation of the exchange in CCXT is broken
 * ``'maintenance'`` means regular maintenance, and the ``eta`` field should contain the datetime when the exchange is expected to be operational again

Borrow Rates
------------

 *margin only*

When short trading or trading with leverage on a spot market, currency must be borrowed. Interest is accrued for the borrowed currency.

Data on the borrow rate for a currency can be retrieved using


 * ``fetchBorrowRate ()`` for a single currencies borrow rate
 * ``fetchBorrowRates ()`` for all currencies borrow rates
 * ``fetchBorrowRatesPerSymbol ()`` for the borrow rates of currencies in individual markets

.. code-block:: Javascript

   fetchBorrowRate (code, params = {})

Parameters


 * **code** (String) Unified CCXT currency code, required (e.g. ``"USDT"``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"marginMode": "cross"}``\ )

Returns


 * A :ref:`transaction structure <transaction structure>`

.. code-block:: Javascript

   fetchBorrowRates (params = {})

Parameters


 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"marginMode": "cross"}``\ )

Returns


 * A dictionary of :ref:`borrow rate structures <borrow rate structure>` with unified currency codes as keys

.. code-block:: Javascript

   fetchBorrowRatesPerSymbol (params = {})

Parameters


 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"marginMode": "cross"}``\ )

Returns


 * A dictionary of :ref:`borrow rate structures <borrow rate structure>` with unified market symbols as keys

Borrow Rate Structure
^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   {
     currency: 'USDT',  // Unified currency code
     rate: 0.0006,  // A ratio of the rate that interest is accrued at
     period: 86400000,  // The amount of time in milliseconds that is required to accrue the interest amount specified by rate
     timestamp: 1646956800000,  // Timestamp for when the currency had this rate
     datetime: '2022-03-11T00:00:00.000Z',  // Datetime for when the currency had this rate
     info: [ ... ]
   }

Borrow Rate History
-------------------

 *margin only*

The ``fetchBorrowRateHistory`` method retrieves a history of a currencies borrow interest rate at specific time slots

.. code-block:: Javascript

   fetchBorrowRateHistory (code, since = undefined, limit = undefined, params = {})

Parameters


 * **code** (String) *required* Unified CCXT currency code (e.g. ``"USDT"``\ )
 * **since** (Integer) Timestamp for the earliest borrow rate (e.g. ``1645807945000``\ )
 * **limit** (Integer) The maximum number of :ref:`borrow rate structures <borrow rate structure>` to retrieve (e.g. ``10``\ )
 * **params** (Dictionary) Extra parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * An array of :ref:`borrow rate structures <borrow rate structure>`

Leverage Tiers
--------------

 *contract only*


 * Leverage Tier methods are private on **binance**

The ``fetchLeverageTiers()`` method can be used to obtain the maximum leverage for a market at varying position sizes. It can also be used to obtain the maintenance margin rate, and the max tradeable amount for a market when that information is not available from the market object

While you can obtain the absolute maximum leverage for a market by accessing ``market['limits']['leverage']['max']``\ , for many contract markets, the maximum leverage will depend on the size of your position.

You can access those limits by using


 * ``fetchMarketLeverageTiers()`` (single symbol)
 * ``fetchLeverageTiers([symbol1, symbol2, ...])`` (multiple symbols)
 * ``fetchLeverageTiers()`` (all market symbols)

.. code-block:: Javascript

   fetchMarketLeverageTiers(symbol, params = {})

Parameters


 * **symbol** (String) *required* Unified CCXT symbol (e.g. ``"BTC/USDT:USDT"``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"settle": "usdt"}``\ )

Returns


 * a :ref:`leverage-tiers-structure <leverage tiers structure>`

.. code-block:: Javascript

   fetchLeverageTiers(symbols = undefined, params = {})

Parameters


 * **symbols** ([String]) Unified CCXT symbol (e.g. ``"BTC/USDT:USDT"``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"settle": "usdt"}``\ )

Returns


 * an array of :ref:`leverage-tiers-structures <leverage tiers structure>`

Leverage Tiers Structure
^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   [
       {
           "tier": 1,                       // tier index
           "notionalCurrency": "USDT",      // the currency that minNotional and maxNotional are in
           "minNotional": 0,                // the lowest amount of this tier // stake = 0.0
           "maxNotional": 10000,            // the highest amount of this tier // max stake amount at 75x leverage = 133.33333333333334
           "maintenanceMarginRate": 0.0065, // maintenance margin rate
           "maxLeverage": 75,               // max available leverage for this market when the value of the trade is > minNotional and < maxNotional
           "info": { ... }                  // Response from exchange
       },
       {
           "tier": 2,
           "notionalCurrency": "USDT",
           "minNotional": 10000,            // min stake amount at 50x leverage = 200.0
           "maxNotional": 50000,            // max stake amount at 50x leverage = 1000.0
           "maintenanceMarginRate": 0.01,
           "maxLeverage": 50,
           "info": { ... },
       },
       ...
       {
           "tier": 9,
           "notionalCurrency": "USDT",
           "minNotional": 20000000,
           "maxNotional": 50000000,
           "maintenanceMarginRate": 0.5,
           "maxLeverage": 1,
           "info": { ... },
       },
   ]

In the example above:


 * stakes below 133.33       = a max leverage of 75
 * stakes from 200 + 1000    = a max leverage of 50
 * a stake amount of 150     = a max leverage of (10000 / 150)   = 66.66
 * stakes between 133.33-200 = a max leverage of (10000 / stake) = 50.01 -> 74.99

 **Note for Huobi users:** Huobi uses both leverage and amount to determine maintenance margin rates: https://www.huobi.com/support/en-us/detail/900000089903

Funding Rate
------------

 *contract only*

Data on the current, most recent, and next funding rates can be obtained using the methods


 * ``fetchFundingRates ()`` for all market symbols
 * ``fetchFundingRates ([ symbol1, symbol2, ... ])`` for multiple market symbols
 * ``fetchFundingRate (symbol)`` for a single market symbol

.. code-block:: Javascript

   fetchFundingRate (symbol, params = {})

Parameters


 * **symbol** (String) *required* Unified CCXT symbol (e.g. ``"BTC/USDT:USDT"``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * a :ref:`funding rate structure <funding rate structure>`

.. code-block:: Javascript

   fetchFundingRates (symbols = undefined, params = {})

Parameters


 * **symbols** ([String]) An optional array/list of unified CCXT symbols (e.g. ``["BTC/USDT:USDT", "ETH/USDT:USDT"]``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * a dictionary of :ref:`funding rate structures <funding rate structure>` indexed by market symbols

Funding Rate Structure
^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: Javascript

   {
       info: { ... },
       symbol: 'BTC/USDT:USDT',
       markPrice: 39294.43,
       indexPrice: 39291.78,
       interestRate: 0.0003,
       estimatedSettlePrice: undefined,
       timestamp: undefined,
       datetime: undefined,
       fundingRate: 0.000072,
       fundingTimestamp: 1645833600000,
       fundingDatetime: '2022-02-26T00:00:00.000Z',
       nextFundingRate: -0.000018,
       nextFundingTimestamp: undefined,
       nextFundingDatetime: undefined,
       previousFundingRate: undefined,
       previousFundingTimestamp: undefined,
       previousFundingDatetime: undefined
   }

Funding Rate History
--------------------

 *contract only*

.. code-block:: Javascript

   fetchFundingRateHistory (symbol = undefined, since = undefined, limit = undefined, params = {})

Parameters


 * **symbol** (String) Unified CCXT symbol (e.g. ``"BTC/USDT:USDT"``\ )
 * **since** (Integer) Timestamp for the earliest funding rate (e.g. ``1645807945000``\ )
 * **limit** (Integer) The maximum number of funding rates to retrieve (e.g. ``10``\ )
 * **params** (Dictionary) Extra parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * An array of :ref:`funding rate history structures <funding rate history structure>`

Funding Rate History Structure
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: Javascript

   {
       info: { ... },
       symbol: "BTC/USDT:USDT",
       fundingRate: -0.000068,
       timestamp: 1642953600000,
       datetime: "2022-01-23T16:00:00.000Z"
   }

Open Interest
-------------

 *contract only*

Use the ``fetchOpenInterest`` method to get the current open interest for a symbol from the exchange.

.. code-block:: JavaScript

   fetchOpenInterest (symbol, params = {})

Parameters


 * **symbol** (String) Unified CCXT market symbol (e.g. ``"BTC/USDT:USDT"``\ )
 * **params** (Dictionary) Extra parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * A dictionary of :ref:`open interest structures <open interest structure>`

Open Interest History
---------------------

 *contract only*

Use the ``fetchOpenInterestHistory`` method to get a history of open interest for a symbol from the exchange.

.. code-block:: JavaScript

   fetchOpenInterestHistory (symbol, timeframe = '5m', since = undefined, limit = undefined, params = {})

Parameters


 * **symbol** (String) Unified CCXT market symbol (e.g. ``"BTC/USDT:USDT"``\ )
 * **timeframe** (String) Check exchange.timeframes for available values
 * **since** (Integer) Timestamp for the earliest open interest record (e.g. ``1645807945000``\ )
 * **limit** (Integer) The maximum number of :ref:`open interest structures <open interest structures>` to retrieve (e.g. ``10``\ )
 * **params** (Dictionary) Extra parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

 **Note for OKX users:** instead of a unified symbol okx.fetchOpenInterestHistory expects a unified currency code in the **symbol** argument (e.g. ``'BTC'``\ ).

Returns


 * An array of :ref:`open interest structures <open interest structure>`

Open Interest Structure
^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   {
       symbol: 'BTC/USDT',
       baseVolume: 80872.801, // deprecated
       quoteVolume: 3508262107.38, // deprecated
       openInterestAmount: 80872.801,
       openInterestValue: 3508262107.38,
       timestamp: 1649379000000,
       datetime: '2022-04-08T00:50:00.000Z',
       info: {
           symbol: 'BTCUSDT',
           sumOpenInterest: '80872.80100000',
           sumOpenInterestValue: '3508262107.38000000',
           timestamp: '1649379000000'
       }
   }

Positions Risk
--------------

 *contract only*

.. code-block:: Javascript

   fetchPositionsRisk (symbols = undefined, params = {})

Parameters


 * **symbols** ([String]) Unified CCXT symbols (e.g. ``["BTC/USDT:USDT", "ETH/USDT:USDT"]``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"settle": "usdt"}``\ )

Returns


 * A :ref:`position risk structures <position risk structure>`

Positions Risk Structure
~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: JavaScript

   {
       info: { ... },
       symbol: 'CTSI/USDT',
       contracts: 0,
       contractSize: 1,
       unrealizedPnl: 0,
       leverage: 20,
       liquidationPrice: 0.7313,
       collateral: 0,
       notional: 0,
       markPrice: 0.7724,
       entryPrice: 0,
       timestamp: 1647420354000,
       initialMargin: 0,
       initialMarginPercentage: 0.05,
       maintenanceMargin: 0,
       maintenanceMarginPercentage: 0.01,
       marginRatio: 0.4881,
       datetime: "2022-03-16T08:45:54.000Z",
       marginMode: 'cross',
       side: "long",
       hedged: false,
       percentage: 78
   }

Private API
===========



In order to be able to access your user account, perform algorithmic trading by placing market and limit orders, query balances, deposit and withdraw funds and so on, you need to obtain your API keys for authentication from each exchange you want to trade with. They usually have it available on a separate tab or page within your user account settings. API keys are exchange-specific and cannnot be interchanged under any circumstances.

The exchanges' private APIs will usually allow the following types of interaction:


 * the current state of the user's account balance can be obtained with the ``fetchBalance()`` method as described in the :ref:`Account Balance <account balance>` section
 * the user can place and cancel orders with ``createOrder()``\ , ``cancelOrder()``\ , as well as fetch current open orders and the past order history with methods like ``fetchOrder``\ , ``fetchOrders()``\ , ``fetchOpenOrder()``\ , ``fetchOpenOrders()``\ , ``fetchCanceledOrders``\ , ``fetchClosedOrder``\ , ``fetchClosedOrders``\ , as described in the section on :ref:`Orders <orders>`
 * the user can query the history of past trades executed with their account using ``fetchMyTrades``\ , as described in the :ref:`My Trades <my trades>` section, also see `How Orders Are Related To Trades <https://docs.ccxt.com/en/latest/manual.html#how-orders-are-related-to-trades>`__
 * the user can query their positions with ``fetchPositions()`` and ``fetchPosition()`` as described in the :ref:`Positions <positions>` section
 * the user can fetch the history of their transactions (on-chain *transactions* which are either *deposits* to the exchange account or *withdrawals* from the exchange account) with ``fetchTransactions()``\ , or with ``fetchDeposit()``\ , ``fetchDeposits()`` ``fetchWithdrawal()``\ , and ``fetchWithdrawals()`` separately, depending on what is available from the exchange API
 * if the exchange API provides a ledger endpoint, the user can fetch a history of all money movements that somehow affected the balance, with ``fetchLedger`` that will return all accounting ledger entries such as trades, deposits, withdrawals, internal transfers between accounts, rebates, bonuses, fees, staking profits and so on, as described in the :ref:`Ledger <ledger>` section.

Authentication
--------------

Authentication with all exchanges is handled automatically if provided with proper API keys. The process of authentication usually goes through the following pattern:


#. Generate new nonce. A nonce is an integer, often a Unix Timestamp in seconds or milliseconds (since epoch January 1, 1970). The nonce should be unique to a particular request and constantly increasing, so that no two requests share the same nonce. Each next request should have greater nonce than the previous request. **The default nonce is a 32-bit Unix Timestamp in seconds.**
#. Append public apiKey and nonce to other endpoint params, if any, then serialize the whole thing for signing.
#. Sign the serialized params using HMAC-SHA256/384/512 or MD5 with your secret key.
#. Append the signature in Hex or Base64 and nonce to HTTP headers or body.

This process may differ from exchange to exchange. Some exchanges may want the signature in a different encoding, some of them vary in header and body param names and formats, but the general pattern is the same for all of them.

 **You should not share the same API keypair across multiple instances of an exchange running simultaneously, in separate scripts or in multiple threads. Using the same keypair from different instances simultaneously may cause all sorts of unexpected behaviour.**

 **DO NOT REUSE API KEYS WITH DIFFERENT SOFTWARE! The other software will screw your nonce too high. If you get :ref:`InvalidNonce <invalid nonce>` errors – make sure to generate a fresh new keypair first and foremost.**

The authentication is already handled for you, so you don't need to perform any of those steps manually unless you are implementing a new exchange class. The only thing you need for trading is the actual API key pair.

API Keys Setup
^^^^^^^^^^^^^^

Required Credentials
~~~~~~~~~~~~~~~~~~~~

The API credentials usually include the following:


 * ``apiKey``. This is your public API Key and/or Token. This part is *non-secret*\ , it is included in your request header or body and sent over HTTPS in open text to identify your request. It is often a string in Hex or Base64 encoding or an UUID identifier.
 * ``secret``. This is your private key. Keep it secret, don't tell it to anybody. It is used to sign your requests locally before sending them to exchanges. The secret key does not get sent over the internet in the request-response process and should not be published or emailed. It is used together with the nonce to generate a cryptographically strong signature. That signature is sent with your public key to authenticate your identity. Each request has a unique nonce and therefore a unique cryptographic signature.
 * ``uid``. Some exchanges (not all of them) also generate a user id or *uid* for short. It can be a string or numeric literal. You should set it, if that is explicitly required by your exchange. See :ref:`their docs <exchanges>` for details.
 * ``password``. Some exchanges (not all of them) also require your password/phrase for trading. You should set this string, if that is explicitly required by your exchange. See :ref:`their docs <exchanges>` for details.

In order to create API keys find the API tab or button in your user settings on the exchange website. Then create your keys and copy-paste them to your config file. Your config file permissions should be set appropriately, unreadable to anyone except the owner.

 **Remember to keep your apiKey and secret key safe from unauthorized use, do not send or tell it to anybody. A leak of the secret key or a breach in security can cost you a fund loss.**

Credential Validation
^^^^^^^^^^^^^^^^^^^^^

For checking if the user has supplied all the required credentials the ``Exchange`` base class has a method called ``exchange.checkRequiredCredentials()`` or ``exchange.check_required_credentials()``. Calling that method will throw an ``AuthenticationError``\ , if some of the credentials are missing or empty. The ``Exchange`` base class also has  property ``exchange.requiredCredentials`` that allows a user to see which credentials are required for this or that exchange, as shown below:

.. code-block:: JavaScript

   // JavaScript
   const ccxt = require ('ccxt')
   const exchange = new ccxt.binance()
   console.log (exchange.requiredCredentials) // prints required credentials
   exchange.checkRequiredCredentials() // throw AuthenticationError

.. code-block:: Python

   # Python
   import ccxt
   exchange = ccxt.coinbasepro()
   print(exchange.requiredCredentials)  # prints required credentials
   exchange.check_required_credentials()  # raises AuthenticationError

.. code-block:: PHP

   // PHP
   include 'ccxt.php';
   $exchange = new \ccxt\bittrex ();
   var_dump($exchange->requiredCredentials); // prints required credentials
   $exchange->check_required_credentials(); // throws AuthenticationError

Configuring API Keys
^^^^^^^^^^^^^^^^^^^^

To set up an exchange for trading just assign the API credentials to an existing exchange instance or pass them to exchange constructor upon instantiation, like so:

.. code-block:: JavaScript

   // JavaScript

   const ccxt = require ('ccxt')

   // any time
   let kraken = new ccxt.kraken ()
   kraken.apiKey = 'YOUR_KRAKEN_API_KEY'
   kraken.secret = 'YOUR_KRAKEN_SECRET_KEY'

   // upon instantiation
   let okcoinusd = new ccxt.okcoinusd ({
       apiKey: 'YOUR_OKCOIN_API_KEY',
       secret: 'YOUR_OKCOIN_SECRET_KEY',
   })

   // from variable id
   const exchangeId = 'binance'
       , exchangeClass = ccxt[exchangeId]
       , exchange = new exchangeClass ({
           'apiKey': 'YOUR_API_KEY',
           'secret': 'YOUR_SECRET',
       })

.. code-block:: Python

   # Python

   import ccxt

   # any time
   bitfinex = ccxt.bitfinex ()
   bitfinex.apiKey = 'YOUR_BFX_API_KEY'
   bitfinex.secret = 'YOUR_BFX_SECRET'

   # upon instantiation
   hitbtc = ccxt.hitbtc ({
       'apiKey': 'YOUR_HITBTC_API_KEY',
       'secret': 'YOUR_HITBTC_SECRET_KEY',
   })

   # from variable id
   exchange_id = 'binance'
   exchange_class = getattr(ccxt, exchange_id)
   exchange = exchange_class({
       'apiKey': 'YOUR_API_KEY',
       'secret': 'YOUR_SECRET',
   })

.. code-block:: PHP

   // PHP

   include 'ccxt.php'

   // any time
   $quoinex = new \ccxt\quoinex ();
   $quoinex->apiKey = 'YOUR_QUOINE_API_KEY';
   $quoinex->secret = 'YOUR_QUOINE_SECRET_KEY';

   // upon instantiation
   $zaif = new \ccxt\zaif (array (
       'apiKey' => 'YOUR_ZAIF_API_KEY',
       'secret' => 'YOUR_ZAIF_SECRET_KEY'
   ));

   // from variable id
   $exchange_id = 'binance';
   $exchange_class = "\\ccxt\\$exchange_id";
   $exchange = new $exchange_class (array (
       'apiKey' => 'YOUR_API_KEY',
       'secret' => 'YOUR_SECRET',
   ));

Note that your private requests will fail with an exception or error if you don't set up your API credentials before you start trading. To avoid character escaping **always write your credentials in single quotes**\ , not double quotes (\ ``'VERY_GOOD'``\ , ``"VERY_BAD"``\ ).

Sign In
^^^^^^^

Some exchanges required you to sign in prior to calling private methods, which can be done using the ``signIn`` method

.. code-block:: Javascript

   signIn (params = {})

Parameters


 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"2fa": "329293"}``\ )

Returns


 * response from the exchange

Overriding The Nonce
^^^^^^^^^^^^^^^^^^^^

 **The default nonce is defined by the underlying exchange. You can override it with a milliseconds-nonce if you want to make private requests more frequently than once per second! Most exchanges will throttle your requests if you hit their rate limits, read `API docs for your exchange <https://github.com/ccxt/ccxt/wiki/Exchanges>`__ carefully!**

In case you need to reset the nonce it is much easier to create another pair of keys for using with private APIs. Creating new keys and setting up a fresh unused keypair in your config is usually enough for that.

In some cases you are unable to create new keys due to lack of permissions or whatever. If that happens you can still override the nonce. Base market class has the following methods for convenience:


 * ``seconds ()``\ : returns a Unix Timestamp in seconds.
 * ``milliseconds ()``\ : same in milliseconds (ms = 1000 * s, thousandths of a second).
 * ``microseconds ()``\ : same in microseconds (μs = 1000 * ms, millionths of a second).

There are exchanges that confuse milliseconds with microseconds in their API docs, let's all forgive them for that, folks. You can use methods listed above to override the nonce value. If you need to use the same keypair from multiple instances simultaneously use closures or a common function to avoid nonce conflicts. In Javascript you can override the nonce by providing a ``nonce`` parameter to the exchange constructor or by setting it explicitly on exchange object:

.. code-block:: JavaScript

   // JavaScript

   // 1: custom nonce redefined in constructor parameters
   let nonce = 1
   let kraken1 = new ccxt.kraken ({ nonce: () => nonce++ })

   // 2: nonce redefined explicitly
   let kraken2 = new ccxt.kraken ()
   kraken2.nonce = function () { return nonce++ } // uses same nonce as kraken1

   // 3: milliseconds nonce
   let kraken3 = new ccxt.kraken ({
       nonce: function () { return this.milliseconds () },
   })

   // 4: newer ES syntax
   let kraken4 = new ccxt.kraken ({
       nonce () { return this.milliseconds () },
   })

In Python and PHP you can do the same by subclassing and overriding nonce function of a particular exchange class:

.. code-block:: Python

   # Python

   # 1: the shortest
   coinbasepro = ccxt.coinbasepro({'nonce': ccxt.Exchange.milliseconds})

   # 2: custom nonce
   class MyKraken(ccxt.kraken):
       n = 1
       def nonce(self):
           return self.n += 1

   # 3: milliseconds nonce
   class MyBitfinex(ccxt.bitfinex):
       def nonce(self):
           return self.milliseconds()

   # 4: milliseconds nonce inline
   hitbtc = ccxt.hitbtc({
       'nonce': lambda: int(time.time() * 1000)
   })

   # 5: milliseconds nonce
   acx = ccxt.acx({'nonce': lambda: ccxt.Exchange.milliseconds()})

.. code-block:: PHP

   // PHP

   // 1: custom nonce value
   class MyOKCoinUSD extends \ccxt\okcoinusd {
       public function __construct ($options = array ()) {
           parent::__construct (array_merge (array ('i' => 1), $options));
       }
       public function nonce () {
           return $this->i++;
       }
   }

   // 2: milliseconds nonce
   class MyZaif extends \ccxt\zaif {
       public function __construct ($options = array ()) {
           parent::__construct (array_merge (array ('i' => 1), $options));
       }
       public function nonce () {
           return $this->milliseconds ();
       }
   }

Accounts
--------

You can get all the accounts associated with a profile by using the ``fetchAccounts()`` method

.. code-block:: JavaScript

   fetchAccounts (params = {})

Accounts Structure
^^^^^^^^^^^^^^^^^^

The ``fetchAccounts()`` method will return a structure like shown below:

.. code-block:: JavaScript

   [
       {
           id: "s32kj302lasli3930",
           type: "main",
           name: "main",
           code: "USDT",
           info: { ... }
       },
       {
           id: "20f0sdlri34lf90",
           name: "customAccount",
           type: "margin",
           code: "USDT",
           info: { ... }
       },
       {
           id: "4oidfk40dadeg4328",
           type: "spot",
           name: "spotAccount32",
           code: "BTC",
           info: { ... }
       },
       ...
   ]

Types of account is one of the :ref:`unified account types <###Account-Balance>` or ``subaccount``

Account Balance
---------------

To query for balance and get the amount of funds available for trading or funds locked in orders, use the ``fetchBalance`` method:

.. code-block:: JavaScript

   fetchBalance (params = {})

Parameters


 * **params** (Dictionary) Extra parameters specific to the exchange API endpoint (e.g. ``{"currency": "usdt"}``\ )

Returns


 * A :ref:`balance structure <balance structure>`

Balance Structure
^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   {
       'info':  { ... },    // the original untouched non-parsed reply with details
       'timestamp': 1499280391811, // Unix Timestamp in milliseconds (seconds * 1000)
       'datetime': '2017-07-05T18:47:14.692Z', // ISO8601 datetime string with milliseconds

       //-------------------------------------------------------------------------
       // indexed by availability of funds first, then by currency

       'free':  {           // money, available for trading, by currency
           'BTC': 321.00,   // floats...
           'USD': 123.00,
           ...
       },

       'used':  { ... },    // money on hold, locked, frozen, or pending, by currency

       'total': { ... },    // total (free + used), by currency

       //-------------------------------------------------------------------------
       // indexed by currency first, then by availability of funds

       'BTC':   {           // string, three-letter currency code, uppercase
           'free': 321.00   // float, money available for trading
           'used': 234.00,  // float, money on hold, locked, frozen or pending
           'total': 555.00, // float, total balance (free + used)
       },

       'USD':   {           // ...
           'free': 123.00   // ...
           'used': 456.00,
           'total': 579.00,
       },

       ...
   }

The ``timestamp`` and ``datetime`` values may be undefined or missing if the underlying exchange does not provide them.

Some exchanges may not return full balance info. Many exchanges do not return balances for your empty or unused accounts. In that case some currencies may be missing in returned balance structure.

.. code-block:: JavaScript

   // JavaScript
   (async () => {
       console.log (await exchange.fetchBalance ())
   }) ()

.. code-block:: Python

   # Python
   print (exchange.fetch_balance ())

.. code-block:: PHP

   // PHP
   var_dump ($exchange->fetch_balance ());

Orders
------

.. code-block:: diff

   - this part of the unified API is currenty a work in progress
   - there may be some issues and missing implementations here and there
   - contributions, pull requests and feedback appreciated

Querying Orders
^^^^^^^^^^^^^^^

Most of the time you can query orders by an id or by a symbol, though not all exchanges offer a full and flexible set of endpoints for querying orders. Some exchanges might not have a method for fetching recently closed orders, the other can lack a method for getting an order by id, etc. The ccxt library will target those cases by making workarounds where possible.

The list of methods for querying orders consists of the following:


 * ``fetchCanceledOrders (symbol = undefined, since = undefined, limit = undefined, params = {})``
 * ``fetchClosedOrder (id, symbol = undefined, params = {})``
 * ``fetchClosedOrders (symbol = undefined, since = undefined, limit = undefined, params = {})``
 * ``fetchOpenOrder (id, symbol = undefined, params = {})``
 * ``fetchOpenOrders (symbol = undefined, since = undefined, limit = undefined, params = {})``
 * ``fetchOrder (id, symbol = undefined, params = {})``
 * ``fetchOrders (symbol = undefined, since = undefined, limit = undefined, params = {})``

Note that the naming of those methods indicates if the method returns a single order or multiple orders (an array/list of orders). The ``fetchOrder()`` method requires a mandatory order id argument (a string). Some exchanges also require a symbol to fetch an order by id, where order ids can intersect with various trading pairs. Also, note that all other methods above return an array (a list) of orders. Most of them will require a symbol argument as well, however, some exchanges allow querying with a symbol unspecified (meaning *all symbols*\ ).

The library will throw a NotSupported exception if a user calls a method that is not available from the exchange or is not implemented in ccxt.

To check if any of the above methods are available, look into the ``.has`` property of the exchange:

.. code-block:: JavaScript

   // JavaScript
   'use strict';

   const ccxt = require ('ccxt')
   const id = 'poloniex'
   exchange = new ccxt[id] ()
   console.log (exchange.has)

.. code-block:: Python

   # Python
   import ccxt
   id = 'binance'
   exchange = getattr(ccxt, id)()
   print(exchange.has)

.. code-block:: PHP

   // PHP
   $exchange = new \ccxt\bitfinex();
   print_r ($exchange->has); // or var_dump

A typical structure of the ``.has`` property usually contains the following flags corresponding to order API methods for querying orders:

.. code-block:: JavaScript

   exchange.has = {

       // ... other flags ...

       'fetchOrder': true, // available from the exchange directly and implemented in ccxt
       'fetchOrders': false, // not available from the exchange or not implemented in ccxt
       'fetchOpenOrders': true,
       'fetchClosedOrders': 'emulated', // not available from the exchange, but emulated in ccxt

       // ... other flags ...

   }

The meanings of boolean ``true`` and ``false`` are obvious. A string value of ``emulated`` means that particular method is missing in the exchange API and ccxt will workaround that where possible on the client-side.

Understanding The Orders API Design
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The exchanges' order management APIs differ by design. The user has to understand the purpose of each specific method and how they're combined together into a complete order API:


 * ``fetchCanceledOrders()``\ - fetches a list of canceled orders
 * ``fetchClosedOrder()``\ - fetches a single closed order by order id
 * ``fetchClosedOrders()`` – fetches a list of closed (or canceled) orders.
 * ``fetchMyTrades()`` – though not a part of the orders' API, it is closely related, since it provides the history of settled trades.
 * ``fetchOpenOrder()``\ - fetches a single open order by order id
 * ``fetchOpenOrders()`` – fetches a list of open orders.
 * ``fetchOrder()`` – fetches a single order (open or closed) by order ``id``.
 * ``fetchOrders()`` – fetches a list of all orders (either open or closed/canceled).

The majority of the exchanges will have a way of fetching currently-open orders. Thus, the ``exchange.has['fetchOpenOrders']``. If that method is not available, then most likely the ``exchange.has['fetchOrders']`` that will provide a list of all orders. The exchange will return a list of open orders either from ``fetchOpenOrders()`` or from ``fetchOrders()``. One of the two methods is usually available from any exchange.

Some exchanges will provide the order history, other exchanges will not. If the underlying exchange provides the order history, then the ``exchange.has['fetchClosedOrders']`` or the ``exchange.has['fetchOrders']``. If the underlying exchange does not provide the order history, then ``fetchClosedOrders()`` and ``fetchOrders()`` are not available. In the latter case, the user is required to build a local cache of orders and track the open orders using ``fetchOpenOrders()`` and ``fetchOrder()`` for order statuses and for marking them as closed locally in the userland (when they're not open anymore).

If the underlying exchange does not have methods for order history (\ ``fetchClosedOrders()`` and ``fetchOrders()``\ ), then it will provide ``fetchOpenOrders`` + the trade history with ``fetchMyTrades`` (see `How Orders Are Related To Trades <https://docs.ccxt.com/en/latest/manual.html#how-orders-are-related-to-trades>`__\ ). That set of information is in many cases enough for tracking in a live-trading robot. If there's no order history – you have to track your live orders and restore historical info from open orders and historical trades.

In general, the underlying exchanges will usually provide one or more of the following types of historical data:


 * ``fetchClosedOrders()``
 * ``fetchOrders()``
 * ``fetchMyTrades()``

Any of the above three methods may be missing, if any other of the three methods is present.

If the underlying exchange does not provide historical orders, the CCXT library will not emulate the missing functionality – it has to be added on the user side where necessary.

 **Please, note, that a certain method may be missing either because the exchange does not have a corresponding API endpoint, or because CCXT has not implemented it yet (the library is also a work in progress). In the latter case, the missing method will be added as soon as possible.**

Querying Multiple Orders And Trades
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

All methods returning lists of trades and lists of orders, accept the second ``since`` argument and the third ``limit`` argument:


 * ``fetchTrades()`` (public)
 * ``fetchMyTrades()`` (private)
 * ``fetchOrders()``
 * ``fetchOpenOrders()``
 * ``fetchClosedOrders()``
 * ``fetchCanceledOrders()``

The second  argument ``since`` reduces the array by timestamp, the third ``limit`` argument reduces by number (count) of returned items.

If the user does not specify ``since``\ , the ``fetchTrades()/fetchOrders()`` methods will return the default set of results from the exchange. The default set is exchange-specific, some exchanges will return trades or recent orders starting from the date of listing a pair on the exchange, other exchanges will return a reduced set of trades or orders (like, last 24 hours, last 100 trades, first 100 orders, etc). If the user wants precise control over the timeframe, the user is responsible for specifying the ``since`` argument.

 **NOTE: not all exchanges provide means for filtering the lists of trades and orders by starting time, so, the support for ``since`` and ``limit`` is exchange-specific. However, most exchanges do provide at least some alternative for "pagination" and "scrolling" which can be overrided with extra ``params`` argument.**

Some exchanges do not have a method for fetching closed orders or all orders. They will offer just the ``fetchOpenOrders()`` endpoint, and sometimes also a ``fetchOrder`` endpoint as well. Those exchanges don't have any methods for fetching the order history. To maintain the order history for those exchanges the user has to store a dictionary or a database of orders in the userland and update the orders in the database after calling methods like ``createOrder()``\ , ``fetchOpenOrders()``\ , ``cancelOrder()``\ , ``cancelAllOrders()``.

By Order Id
~~~~~~~~~~~

To get the details of a particular order by its id, use the ``fetchOrder()`` / ``fetch_order()`` method. Some exchanges also require a symbol even when fetching a particular order by id.

The signature of the fetchOrder/fetch_order method is as follows:

.. code-block:: JavaScript

   if (exchange.has['fetchOrder']) {
       //  you can use the params argument for custom overrides
       let order = await exchange.fetchOrder (id, symbol = undefined, params = {})
   }

 **Some exchanges don't have an endpoint for fetching an order by id, ccxt will emulate it where possible.** For now it may still be missing here and there, as this is a work in progress.

You can pass custom overrided key-values in the additional params argument to supply a specific order type, or some other setting if needed.

Below are examples of using the fetchOrder method to get order info from an authenticated exchange instance:

.. code-block:: JavaScript

   // JavaScript
   (async function () {
       const order = await exchange.fetchOrder (id)
       console.log (order)
   }) ()

.. code-block:: Python

   # Python 3 (synchronous)
   if exchange.has['fetchOrder']:
       order = exchange.fetch_order(id)
       print(order)

   # Python 3.5+ asyncio (asynchronous)
   import asyncio
   import ccxt.async_support as ccxt
   if exchange.has['fetchOrder']:
       order = asyncio.run(exchange.fetch_order(id))
       print(order)

.. code-block:: PHP

   // PHP
   if ($exchange->has['fetchOrder']) {
       $order = $exchange->fetch_order($id);
       var_dump($order);
   }

All Orders
~~~~~~~~~~

.. code-block:: JavaScript

   if (exchange.has['fetchOrders'])
       exchange.fetchOrders (symbol = undefined, since = undefined, limit = undefined, params = {})

 **Some exchanges don't have an endpoint for fetching all orders, ccxt will emulate it where possible.** For now it may still be missing here and there, as this is a work in progress.

Open Orders
~~~~~~~~~~~

.. code-block:: JavaScript

   if (exchange.has['fetchOpenOrders'])
       exchange.fetchOpenOrders (symbol = undefined, since = undefined, limit = undefined, params = {})

Closed Orders
~~~~~~~~~~~~~

Do not confuse *closed orders* with *trades* aka *fills* ! An order can be closed (filled) with multiple opposing trades! So, a *closed order* is not the same as a *trade*. In general, the order does not have a ``fee`` at all, but each particular user trade does have ``fee``\ , ``cost`` and other properties. However, many exchanges propagate those properties to the orders as well.

 **Some exchanges don't have an endpoint for fetching closed orders, ccxt will emulate it where possible.** For now it may still be missing here and there, as this is a work in progress.

.. code-block:: JavaScript

   if (exchange.has['fetchClosedOrders'])
       exchange.fetchClosedOrders (symbol = undefined, since = undefined, limit = undefined, params = {})

Order Structure
^^^^^^^^^^^^^^^

Most of methods returning orders within ccxt unified API will yield an order structure as described below:

.. code-block:: JavaScript

   {
       'id':                '12345-67890:09876/54321', // string
       'clientOrderId':     'abcdef-ghijklmnop-qrstuvwxyz', // a user-defined clientOrderId, if any
       'datetime':          '2017-08-17 12:42:48.000', // ISO8601 datetime of 'timestamp' with milliseconds
       'timestamp':          1502962946216, // order placing/opening Unix timestamp in milliseconds
       'lastTradeTimestamp': 1502962956216, // Unix timestamp of the most recent trade on this order
       'status':      'open',        // 'open', 'closed', 'canceled', 'expired', 'rejected'
       'symbol':      'ETH/BTC',     // symbol
       'type':        'limit',       // 'market', 'limit'
       'timeInForce': 'GTC',         // 'GTC', 'IOC', 'FOK', 'PO'
       'side':        'buy',         // 'buy', 'sell'
       'price':        0.06917684,   // float price in quote currency (may be empty for market orders)
       'average':      0.06917684,   // float average filling price
       'amount':       1.5,          // ordered amount of base currency
       'filled':       1.1,          // filled amount of base currency
       'remaining':    0.4,          // remaining amount to fill
       'cost':         0.076094524,  // 'filled' * 'price' (filling price used where available)
       'trades':     [ ... ],        // a list of order trades/executions
       'fee': {                      // fee info, if available
           'currency': 'BTC',        // which currency the fee is (usually quote)
           'cost': 0.0009,           // the fee amount in that currency
           'rate': 0.002,            // the fee rate (if available)
       },
       'info': { ... },              // the original unparsed order structure as is
   }


 * The ``status`` of an order is usually either ``'open'`` (not filled or partially filled), ``'closed'`` (fully filled), or ``'canceled'`` (unfilled and canceled, or partially filled then canceled).
 * Some exchanges allow the user to specify an expiration timestamp upon placing a new order. If the order is not filled by that time, its ``status`` becomes ``'expired'``.
 * Use the ``filled`` value to determine if the order is filled, partially filled or fully filled, and by how much.
 * The work on ``'fee'`` info is still in progress, fee info may be missing partially or entirely, depending on the exchange capabilities.
 * The ``fee`` currency may be different from both traded currencies (for example, an ETH/BTC order with fees in USD).
 * The ``lastTradeTimestamp`` timestamp may have no value and may be ``undefined/None/null`` where not supported by the exchange or in case of an open order (an order that has not been filled nor partially filled yet).
 * The ``lastTradeTimestamp``\ , if any, designates the timestamp of the last trade, in case the order is filled fully or partially, otherwise ``lastTradeTimestamp`` is ``undefined/None/null``.
 * Order ``status`` prevails or has precedence over the ``lastTradeTimestamp``.
 * The ``cost`` of an order is: ``{ filled * price }``
 * The ``cost`` of an order means the total *quote* volume of the order (whereas the ``amount`` is the *base* volume). The value of ``cost`` should be as close to the actual most recent known order cost as possible. The ``cost`` field itself is there mostly for convenience and can be deduced from other fields.
 * The ``clientOrderId`` field can be set upon placing orders by the user with :ref:`custom order params <custom order params>`. Using the ``clientOrderId`` the user can later distinguish between own orders. This is only available for the exchanges that do support ``clientOrderId`` at this time.

timeInForce
~~~~~~~~~~~

The ``timeInForce`` field may be ``undefined/None/null`` if not specified by the exchange. The unification of ``timeInForce`` is a work in progress.

Possible values for the\ ``timeInForce`` field:


 * ``'GTC'`` = *Good Till Cancel(ed)*\ , the order stays on the orderbook until it is matched or canceled.
 * ``'IOC'`` = *Immediate Or Cancel*\ , the order has to be matched immediately and filled either partially or completely, the unfilled remainder is canceled (or the entire order is canceled).
 * ``'FOK'`` = *Fill Or Kill*\ , the order has to get fully filled and closed immediately, otherwise the entire order is canceled.
 * ``'PO'`` = *Post Only*\ , the order is either placed as a maker order, or it is canceled. This means the order must be placed on orderbook for at at least time in an unfilled state. The unification of ``PO`` as a ``timeInForce`` option is a work in progress with unified exchanges having ``exchange.has['postOnly'] == True``.

Placing Orders
^^^^^^^^^^^^^^

To place an order use the ``createOrder`` method. You can use the ``id`` from the returned unified :ref:`order structure <order structure>` to query the status and the state of the order later.

.. code-block:: JavaScript

   createOrder (symbol, type, side, amount, price = undefined, params = {})

Parameters


 * **symbol** (String) *required* Unified CCXT market symbol

  * Make sure the symbol in question exists with the target exchange and is available for trading.

 * **side** *required* a string literal for the direction of your order.
  **Unified sides:**

  * ``buy`` give quote currency and receive base currency; for example, buying ``BTC/USD`` means that you will receive bitcoins for your dollars.
  * ``sell`` give base currency and receive quote currency; for example, buying ``BTC/USD`` means that you will receive dollars for your bitcoins.

 * **type** a string literal type of order
  **Unified types:**

  * :doc:`market <market orders>` not allowed by some exchanges, see :ref:`their docs <exchanges>` for details
  * :doc:`limit <limit orders>`
  * see #custom-order-params and #other-order-types for non-unified types

 * **amount**\ , how much of currency you want to trade usually, but not always, in units of the base currency of the trading pair symbol (the units for some exchanges are dependent on the side of the order: see their API docs for details.)
 * **price** the price at which the order is to be fullfilled at in units of the quote currency (ignored in market orders)
 * **params** (Dictionary) Extra parameters specific to the exchange API endpoint (e.g. ``{"settle": "usdt"}``\ )

Returns


 * A successful order call returns a :ref:`order structure <order structure>`

 **Notes on createOrder**


 * Some exchanges will allow to trade with limit orders only.

Some fields from the returned order structure may be ``undefined / None / null`` if that information is not returned from the exchange API's response. The user is guaranteed that the ``createOrder`` method will return a unified :ref:`order structure <order structure>` that will contain at least the order ``id`` and the ``info`` (a raw response from the exchange "as is"):

.. code-block:: JavaScript

   {
       'id': 'string',  // order id
       'info': { ... }, // decoded original JSON response from the exchange as is
   }

Limit Orders
~~~~~~~~~~~~

Limit orders placed on the order book of the exchange for a price specified by the trader. They are fullfilled(closed) when there are no orders in the same market at a better price, and another trader creates a :doc:`market order <market orders>` or an opposite order for a price that matches or exceeds the price of the limit order.

Limit orders may not be fully filled. This happens when the filling order is for a smaller amount than the amount specified by the limit order.

.. code-block:: JavaScript

   // camelCaseNotation
   exchange.createLimitSellOrder (symbol, amount, price, params)
   exchange.createLimitBuyOrder (symbol, amount, price, params)

   // underscore_notation
   exchange.create_limit_sell_order (symbol, amount, price, params)
   exchange.create_limit_buy_order (symbol, amount, price, params)

   // using general createLimitOrder and side = 'buy' or 'sell'
   exchange.createLimitOrder (symbol, side, amount, price, params)
   exchange.create_limit_order (symbol, side, amount, price, params)

   // using general createOrder, type = 'limit' and side = 'buy' or 'sell'
   exchange.createOrder (symbol, 'limit', side, amount, price, params)
   exchange.create_order (symbol, 'limit', side, amount, price, params)

Market Orders
~~~~~~~~~~~~~

 *also known as*


 * market price orders
 * spot price orders
 * instant orders

Market orders are executed immediately by fulfilling one of more already existing orders from the ask side of the exchanges order book. The orders that your market order fulfills are chosen from th top of the order book stack, meaning your market order is fulfilled at the best price available. When placing a market order you don't need to specify the price of the order, and if the price is specified, it will be ignored.

You are not guaranteed that the order will be executed for the price you observe prior to placing your order. There are multiple reasons for this, including:


 * 
  **price slippage** a slight change of the price for the traded market while your order is being executed. Reasons for price slippage include, but are not limited to


  * networking roundtrip latency
  * high loads on the exchange
  * price volatility

 * 
  **unequivocal order sizes** if a market order is for an amount that is larger than the size of the top order on the order book, then after the top order is filled, the market order will proceed to fill the next order in the order book, which means the market order is filled at multiple prices

.. code-block:: JavaScript

   // camelCaseNotation
   exchange.createMarketSellOrder (symbol, amount, params)
   exchange.createMarketBuyOrder (symbol, amount, params)

   // underscore_notation
   exchange.create_market_sell_order (symbol, amount, params)
   exchange.create_market_buy_order (symbol, amount, params)

   // using general createMarketOrder and side = 'buy' or 'sell'
   exchange.createMarketOrder (symbol, side, amount, params)
   exchange.create_market_order (symbol, side, amount, params)

   // using general createOrder, type = 'market' and side = 'buy' or 'sell'
   exchange.createOrder (symbol, 'market', side, amount, ...)
   exchange.create_order (symbol, 'market', side, amount, ...)

 **Note, that some exchanges will not accept market orders (they allow limit orders only).** In order to detect programmatically if the exchange in question does support market orders or not, you can use the ``.has['createMarketOrder']`` exchange property:

.. code-block:: JavaScript

   // JavaScript
   if (exchange.has['createMarketOrder']) {
       ...
   }

.. code-block:: Python

   # Python
   if exchange.has['createMarketOrder']:
       ...

.. code-block:: PHP

   // PHP
   if ($exchange->has['createMarketOrder']) {
       ...
   }

Market Buys
~~~~~~~~~~~

In general, when placing a ``market buy`` or ``market sell`` order the user has to specify just the amount of the base currency to buy or sell. However, with some exchanges market buy orders implement a different approach to calculating the value of the order.

Suppose you're trading BTC/USD and the current market price for BTC is over 9000 USD. For a market buy or market sell you could specify an ``amount`` of 2 BTC and that would result in *plus or minus* 18000 USD (more or less ;)) on your account, depending on the side of the order.

 **With market buys some exchanges require the total cost of the order in the quote currency!** The logic behind it is simple, instead of taking the amount of base currency to buy or sell some exchanges operate with *"how much quote currency you want to spend on buying in total"*.

To place a market buy order with those exchanges you would not specify an amount of 2 BTC, instead you should somehow specify the total cost of the order, that is, 18000 USD in this example. The exchanges that treat ``market buy`` orders in this way have an exchange-specific option ``createMarketBuyOrderRequiresPrice`` that allows specifying the total cost of a ``market buy`` order in two ways.

The first is the default and if you specify the ``price`` along with the ``amount`` the total cost of the order would be calculated inside the lib from those two values with a simple multiplication (\ ``cost = amount * price``\ ). The resulting ``cost`` would be the amount in USD quote currency that will be spent on this particular market buy order.

.. code-block:: JavaScript

   // this example is oversimplified and doesn't show all the code that is
   // required to handle the errors and exchange metadata properly
   // it shows just the concept of placing a market buy order

   const exchange = new ccxt.cex ({
       'apiKey': YOUR_API_KEY,
       'secret': 'YOUR_SECRET',
       // 'options': {
       //     'createMarketBuyOrderRequiresPrice': true, // default
       // },
   })

   ;(async () => {

       // when `createMarketBuyOrderRequiresPrice` is true, we can pass the price
       // so that the total cost of the order would be calculated inside the library
       // by multiplying the amount over price (amount * price)

       const symbol = 'BTC/USD'
       const amount = 2 // BTC
       const price = 9000 // USD
       // cost = amount * price = 2 * 9000 = 18000 (USD)

       // note that we don't use createMarketBuyOrder here, instead we use createOrder
       // createMarketBuyOrder will omit the price and will not work when
       // exchange.options['createMarketBuyOrderRequiresPrice'] = true
       const order = await exchange.createOrder (symbol, 'market', 'buy', amount, price)

       console.log (order)
   }) ()

The second alternative is useful in cases when the user wants to calculate and specify the resulting total cost of the order himself. That can be done by setting the ``createMarketBuyOrderRequiresPrice`` option to ``false`` to switch it off:

.. code-block:: JavaScript

   const exchange = new ccxt.cex ({
       'apiKey': YOUR_API_KEY,
       'secret': 'YOUR_SECRET',
       'options': {
           'createMarketBuyOrderRequiresPrice': false, // switch off
       },
   })

   // or, to switch it off later, after the exchange instantiation, you can do
   exchange.options['createMarketBuyOrderRequiresPrice'] = false

   ;(async () => {

       // when `createMarketBuyOrderRequiresPrice` is true, we can pass the price
       // so that the total cost of the order would be calculated inside the library
       // by multiplying the amount over price (amount * price)

       const symbol = 'BTC/USD'
       const amount = 2 // BTC
       const price = 9000 // USD
       cost = amount * price // ← instead of the amount cost goes ↓ here
       const order = await exchange.createMarketBuyOrder (symbol, cost)
       console.log (order)
   }) ()

More about it:


 * https://github.com/ccxt/ccxt/issues/564#issuecomment-347458566
 * https://github.com/ccxt/ccxt/issues/4914#issuecomment-478199357
 * https://github.com/ccxt/ccxt/issues/4799#issuecomment-470966769
 * https://github.com/ccxt/ccxt/issues/5197#issuecomment-496270785

Emulating Market Orders With Limit Orders

Limit price orders are also known as *limit orders*. Some exchanges accept limit orders only. Limit orders require a price (rate per unit) to be submitted with the order. The exchange will close limit orders if and only if market price reaches the desired level.

.. code-block:: JavaScript

   // camelCaseStyle
   exchange.createLimitBuyOrder (symbol, amount, price[, params])
   exchange.createLimitSellOrder (symbol, amount, price[, params])

   // underscore_style
   exchange.create_limit_buy_order (symbol, amount, price[, params])
   exchange.create_limit_sell_order (symbol, amount, price[, params])

Stop Orders
~~~~~~~~~~~

Stop orders, are placed onto the order book when the price of the underlying asset reaches the trigger price.


 * They can be used to close positions when a certain profit level is reached, or to mitigate a large loss.
 * They can be stand-alone orders (\ :ref:`Trigger <trigger order>`\ , :ref:`Stop Loss <stop loss orders>`\ , :ref:`Take Profit <take profit orders>`\ ).
 * Or they can be attached to a primary order (\ :ref:`Conditional Stop Orders <stopLoss-and-takeProfit-orders-attached-to-a-position>`\ ).
 * Stop Orders can be limit or market orders

Trigger Order
"""""""""""""

Traditional "stop" order (which you might see across exchanges' websites) is now called "trigger" order across CCXT library. Implemented by adding a ``triggerPrice`` parameter. They are independent basic trigger orders that can open and close a position.


 * Activated when price of the underlying asset/contract crosses the ``triggerPrice`` from **any direction**

.. code-block:: JavaScript

   // JavaScript
   const symbol = 'ETH/BTC'
   const type = 'limit' // or 'market'
   const side = 'sell'
   const amount = 123.45 // your amount
   const price = 54.321 // your price
   const params = {
       'triggerPrice': 123.45, // your stop price
   }
   const order = await exchange.createOrder (symbol, type, side, amount, price, params)

.. code-block:: Python

   # Python
   symbol = 'ETH/BTC'
   type = 'limit'  # or 'market'
   side = 'sell'
   amount = 123.45  # your amount
   price = 54.321  # your price
   params = {
       'triggerPrice': 123.45,  # your stop price
   }
   order = exchange.create_order(symbol, type, side, amount, price, params)

.. code-block:: PHP

   // PHP
   $symbol = 'ETH/BTC';
   $type = 'limit'; // or 'market'
   $side = 'sell';
   $amount = 123.45; // your amount
   $price = 54.321; // your price
   $params = {
       'triggerPrice': 123.45, // your stop price
   }
   $order = $exchange->create_order ($symbol, $type, $side, $amount, $price, $params);

Stop Loss Orders
""""""""""""""""

The same as Trigger Orders, but the direction matters. Implemented by specifying a ``stopLossPrice`` parameter.

Stop Loss orders are activated when the price of the underlying asset/contract:


 * drops below the ``stopLossPrice`` from above, for sell orders. (eg: to close a long position, and avoid further losses)
 * rises above the ``stopLossPrice`` from below, for buy orders (eg: to close a short position, and avoid further losses)

Take Profit Orders
""""""""""""""""""

The same as Trigger Orders, but the direction matters. Implemented by specifying a ``takeProfitPrice`` parameter.
Take Profit orders are activated when the price of the underlying:


 * rises above the ``takeProfitPrice`` from below, for sell orders (eg: to close a long position, at a profit)
 * drops below the ``takeProfitPrice`` from above, for buy orders (eg: to close a short position, at a profit)

.. code-block:: JavaScript

   // JavaScript

   // for a stop loss order
   const params = {
       'stopLossPrice': 55.45, // your stop loss price
   }

   // for a take profit order
   const params = {
       'takeProfitPrice': 120.45, // your take profit price
   }

   const order = await exchange.createOrder (symbol, type, side, amount, price, params)

.. code-block:: Python

   # Python

   # for a stop loss order
   params = {
       'stopLossPrice': 55.45,  # your stop loss price
   }

   # for a take profit order
   params = {
       'takeProfitPrice': 120.45,  # your take profit price
   }

   order = exchange.create_order (symbol, type, side, amount, price, params)

.. code-block:: PHP

   // PHP

   // for a stop loss order
   $params = {
       'stopLossPrice': 55.45, // your stop loss price
   }

   // for a take profit order
   $params = {
       'takeProfitPrice': 120.45, // your take profit price
   }

   $order = $exchange->create_order ($symbol, $type, $side, $amount, $price, $params);

StopLoss and TakeProfit orders attached to a position

Some exchanges allow you to specify optional parameters for your order. You can pass your optional parameters and override your query with an associative array using the ``params`` argument to your unified API call. All custom params are exchange-specific, of course, and aren't interchangeable, do not expect those custom params for one exchange to work with another exchange.

.. code-block:: JavaScript

   // JavaScript
   // use a custom order type
   bitfinex.createLimitSellOrder ('BTC/USD', 1, 10, { 'type': 'trailing-stop' })

.. code-block:: Python

   # Python
   # add a custom order flag
   kraken.create_market_buy_order('BTC/USD', 1, {'validate': true})

.. code-block:: PHP

   // PHP
   // add custom user id to your order
   $hitbtc->create_order ('BTC/USD', 'limit', 'buy', 1, 3000, array ('clientOrderId' => '123'));

User-defined ``clientOrderId``
""""""""""""""""""""""""""""""""""

.. code-block:: text

   - this part of the unified API is currenty a work in progress
   - there may be some issues and missing implementations here and there
   - contributions, pull requests and feedback appreciated

The user can specify a custom ``clientOrderId`` field can be set upon placing orders with the ``params``. Using the ``clientOrderId`` one can later distinguish between own orders. This is only available for the exchanges that do support ``clientOrderId`` at this time. For the exchanges that don't support it will either throw an error upon supplying the ``clientOrderId`` or will ignore it setting the ``clientOrderId`` to ``undefined/None/null``.

.. code-block:: JavaScript

   exchange.createOrder (symbol, type, side, amount, price, {
       'clientOrderId': 'Hello',
   })

.. code-block:: Python

   exchange.create_order(symbol, type, side, amount, price, {
       'clientOrderId': 'World',
   })

.. code-block:: PHP

   $exchange->create_order($symbol, $type, $side, $amount, $price, array(
       'clientOrderId' => 'Foobar',
   ))

Editing Orders
--------------

To edit an order, you can use the ``editOrder`` method

.. code-block:: Javascript

   editOrder (id, symbol, type, side, amount, price = undefined, params = {})

Parameters


 * **id** (String) *required* Order id (e.g. ``1645807945000``\ )
 * **symbol** (String) *required* Unified CCXT market symbol
 * **side** (String) *required* the direction of your order.
  **Unified sides:**

  * ``buy`` give quote currency and receive base currency; for example, buying ``BTC/USD`` means that you will receive bitcoins for your dollars.
  * ``sell`` give base currency and receive quote currency; for example, buying ``BTC/USD`` means that you will receive dollars for your bitcoins.

 * **type** (String) *required* type of order
  **Unified types:**

  * :doc:`\ ``market`` <market orders>` not allowed by some exchanges, see :ref:`their docs <exchanges>` for details
  * :doc:`\ ``limit`` <limit orders>`
  * see #custom-order-params and #other-order-types for non-unified types

 * **amount** (Number) *required* how much of currency you want to trade usually, but not always, in units of the base currency of the trading pair symbol (the units for some exchanges are dependent on the side of the order: see their API docs for details.)
 * **price** (Float) the price at which the order is to be fullfilled at in units of the quote currency (ignored in market orders)
 * **params** (Dictionary) Extra parameters specific to the exchange API endpoint (e.g. ``{"settle": "usdt"}``\ )

Returns


 * An :ref:`order structure <order structure>`

Canceling Orders
^^^^^^^^^^^^^^^^

To cancel an existing use


 * ``cancelOrder ()`` for a single order
 * ``cancelOrders ()`` for multiple orders
 * ``cancelAllOrders ()`` for all open orders

.. code-block:: JavaScript

   cancelOrder (id, symbol = undefined, params = {})

Parameters


 * **id** (String) *required* Order id (e.g. ``1645807945000``\ )
 * **symbol** (String) Unified CCXT market symbol **required** on some exchanges (e.g. ``"BTC/USDT"``\ )
 * **params** (Dictionary) Extra parameters specific to the exchange API endpoint (e.g. ``{"settle": "usdt"}``\ )

Returns


 * An :ref:`order structure <order structure>`

.. code-block:: Javascript

   cancelOrders (ids, symbol = undefined, params = {})

Parameters


 * **ids** ([String]) *required* Order ids (e.g. ``1645807945000``\ )
 * **symbol** (String) Unified CCXT market symbol **required** on some exchanges (e.g. ``"BTC/USDT"``\ )
 * **params** (Dictionary) Extra parameters specific to the exchange API endpoint (e.g. ``{"settle": "usdt"}``\ )

Returns


 * An array of :ref:`order structures <order structure>`

.. code-block:: JavaScript

   async cancelAllOrders (symbol = undefined, params = {})

Parameters


 * **symbol** (String) Unified CCXT market symbol **required** on some exchanges (e.g. ``"BTC/USDT"``\ )
 * **params** (Dictionary) Extra parameters specific to the exchange API endpoint (e.g. ``{"settle": "usdt"}``\ )

Returns


 * An array of :ref:`order structures <order structure>`

Exceptions on order canceling

   | price  | amount

   | price  | amount

   | price  | amount

   | price  | amount

.. code-block:: JavaScript

   {
       'info':         { ... },                    // the original decoded JSON as is
       'id':           '12345-67890:09876/54321',  // string trade id
       'timestamp':    1502962946216,              // Unix timestamp in milliseconds
       'datetime':     '2017-08-17 12:42:48.000',  // ISO8601 datetime with milliseconds
       'symbol':       'ETH/BTC',                  // symbol
       'order':        '12345-67890:09876/54321',  // string order id or undefined/None/null
       'type':         'limit',                    // order type, 'market', 'limit' or undefined/None/null
       'side':         'buy',                      // direction of the trade, 'buy' or 'sell'
       'takerOrMaker': 'taker',                    // string, 'taker' or 'maker'
       'price':        0.06917684,                 // float price in quote currency
       'amount':       1.5,                        // amount of base currency
       'cost':         0.10376526,                 // total cost, `price * amount`,
       'fee':          {                           // provided by exchange or calculated by ccxt
           'cost':  0.0015,                        // float
           'currency': 'ETH',                      // usually base currency for buys, quote currency for sells
           'rate': 0.002,                          // the fee rate (if available)
       },
   }


 * The work on ``'fee'`` info is still in progress, fee info may be missing partially or entirely, depending on the exchange capabilities.
 * The ``fee`` currency may be different from both traded currencies (for example, an ETH/BTC order with fees in USD).
 * The ``cost`` of the trade means ``amount * price``. It is the total *quote* volume of the trade (whereas ``amount`` is the *base* volume). The cost field itself is there mostly for convenience and can be deduced from other fields.
 * The ``cost`` of the trade is a *"gross"* value. That is the value pre-fee, and the fee has to be applied afterwards.

Trades By Order Id
^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   // JavaScript
   // fetchOrderTrades (id, symbol = undefined, since = undefined, limit = undefined, params = {})

   if (exchange.has['fetchOrderTrades']) {
       const trades = await exchange.fetchOrderTrades (orderId, symbol, since, limit, params)
   }

.. code-block:: Python

   # Python
   # fetch_order_trades(id, symbol=None, since=None, limit=None, params={})

   if exchange.has['fetchOrderTrades']:
       exchange.fetch_order_trades(order_id, symbol=None, since=None, limit=None, params={})

.. code-block:: PHP

   // PHP
   // fetch_order_trades ($id, $symbol = null, $since = null, $limit = null, $params = array())

   if ($exchange->has['fetchOrderTrades']) {
       $trades = $exchange->fetch_order_trades($order_id, $symbol, $since, $limit, $params);
   }

Ledger
------

The ledger is simply the history of changes, actions done by the user or operations that altered the user's balance in any way, that is, the history of movements of all funds from/to all accounts of the user which includes


 * deposits and withdrawals (funding)
 * amounts incoming and outcoming in result of a trade or an order
 * trading fees
 * transfers between accounts
 * rebates, cashbacks and other types of events that are subject to accounting.

Data on ledger entries can be retrieved using


 * ``fetchLedgerEntry ()`` for a ledger entry
 * ``fetchLedger ( code )`` for multiple ledger entries of the same currency
 * ``fetchLedger ()`` for all ledger entries

.. code-block:: Javascript

   fetchLedgerEntry (id, code = undefined, params = {})

Parameters


 * **id** (String) *required* Ledger entry id
 * **code** (String) Unified CCXT currency code, required (e.g. ``"USDT"``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"type": "deposit"}``\ )

Returns


 * A :ref:`ledger entry structure <ledger entry structure>`

.. code-block:: JavaScript

   async fetchLedger (code = undefined, since = undefined, limit = undefined, params = {})

Parameters


 * **code** (String) Unified CCXT currency code; *required* if fetching all ledger entries for all assets at once is not supported (e.g. ``"USDT"``\ )
 * **since** (Integer) Timestamp (ms) of the earliest time to retrieve withdrawals for (e.g. ``1646940314000``\ )
 * **limit** (Integer) The number of :ref:`ledger entry structures <ledger entry structure>` to retrieve (e.g. ``5``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * An array of :ref:`ledger entry structures <ledger entry structure>`

Ledger Entry Structure
^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   {
       'id': 'hqfl-f125f9l2c9',                // string id of the ledger entry, e.g. an order id
       'direction': 'out',                     // or 'in'
       'account': '06d4ab58-dfcd-468a',        // string id of the account if any
       'referenceId': 'bf7a-d4441fb3fd31',     // string id of the trade, transaction, etc...
       'referenceAccount': '3146-4286-bb71',   // string id of the opposite account (if any)
       'type': 'trade',                        // string, reference type, see below
       'currency': 'BTC',                      // string, unified currency code, 'ETH', 'USDT'...
       'amount': 123.45,                       // absolute number, float (does not include the fee)
       'timestamp': 1544582941735,             // milliseconds since epoch time in UTC
       'datetime': "2018-12-12T02:49:01.735Z", // string of timestamp, ISO8601
       'before': 0,                            // amount of currency on balance before
       'after': 0,                             // amount of currency on balance after
       'status': 'ok',                         // 'ok, 'pending', 'canceled'
       'fee': {                                // object or or undefined
           'cost': 54.321,                     // absolute number on top of the amount
           'currency': 'ETH',                  // string, unified currency code, 'ETH', 'USDT'...
       },
       'info': { ... },                        // raw ledger entry as is from the exchange
   }

Notes on Ledger Entry Structure

 * ``addressFrom`` or ``addressTo`` may be ``undefined/None/null``\ , if the exchange in question does not specify all sides of the transaction
 * The semantics of the ``address`` field is exchange-specific. In some cases it can contain the address of the sender, in other cases it may contain the address of the receiver. The actual value depends on the exchange.
 * The ``updated`` field is the UTC timestamp in milliseconds of the most recent change of status of that funding operation, be it ``withdrawal`` or ``deposit``. It is necessary if you want to track your changes in time, beyond a static snapshot. For example, if the exchange in question reports ``created_at`` and ``confirmed_at`` for a transaction, then the ``updated`` field will take the value of ``Math.max (created_at, confirmed_at)``\ , that is, the timestamp of the most recent change of the status.
 * The ``updated`` field may be ``undefined/None/null`` in certain exchange-specific cases.
 * The ``fee`` substructure may be missing, if not supplied within the reply coming from the exchange.
 * The ``comment`` field may be ``undefined/None/null``\ , otherwise it will contain a message or note defined by the user upon creating the transaction.
 * Be careful when handling the ``tag`` and the ``address``. The ``tag`` is **NOT an arbitrary user-defined string** of your choice! You cannot send user messages and comments in the ``tag``. The purpose of the ``tag`` field is to address your wallet properly, so it must be correct. You should only use the ``tag`` received from the exchange you're working with, otherwise your transaction might never arrive to its destination.

fetchDeposits Examples
^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   // JavaScript
   // fetchDeposits (code = undefined, since = undefined, limit = undefined, params = {})

   if (exchange.has['fetchDeposits']) {
       const deposits = await exchange.fetchDeposits (code, since, limit, params)
   } else {
       throw new Error (exchange.id + ' does not have the fetchDeposits method')
   }

.. code-block:: Python

   # Python
   # fetch_deposits(code = None, since = None, limit = None, params = {})

   if exchange.has['fetchDeposits']:
       deposits = exchange.fetch_deposits(code, since, limit, params)
   else:
       raise Exception (exchange.id + ' does not have the fetch_deposits method')

.. code-block:: PHP

   // PHP
   // fetch_deposits ($code = null, $since = null, $limit = null, $params = {})

   if ($exchange->has['fetchDeposits']) {
       $deposits = $exchange->fetch_deposits ($code, $since, $limit, $params);
   } else {
       throw new Exception ($exchange->id . ' does not have the fetch_deposits method');
   }

fetchWithdrawals Examples
^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   // JavaScript
   // fetchWithdrawals (code = undefined, since = undefined, limit = undefined, params = {})

   if (exchange.has['fetchWithdrawals']) {
       const withdrawals = await exchange.fetchWithdrawals (code, since, limit, params)
   } else {
       throw new Error (exchange.id + ' does not have the fetchWithdrawals method')
   }

.. code-block:: Python

   # Python
   # fetch_withdrawals(code = None, since = None, limit = None, params = {})

   if exchange.has['fetchWithdrawals']:
       withdrawals = exchange.fetch_withdrawals(code, since, limit, params)
   else:
       raise Exception (exchange.id + ' does not have the fetch_withdrawals method')

.. code-block:: PHP

   // PHP
   // fetch_withdrawals ($code = null, $since = null, $limit = null, $params = {})

   if ($exchange->has['fetchWithdrawals']) {
       $withdrawals = $exchange->fetch_withdrawals ($code, $since, $limit, $params);
   } else {
       throw new Exception ($exchange->id . ' does not have the fetch_withdrawals method');
   }

fetchTransactions Examples
^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   // JavaScript
   // fetchTransactions (code = undefined, since = undefined, limit = undefined, params = {})

   if (exchange.has['fetchTransactions']) {
       const transactions = await exchange.fetchTransactions (code, since, limit, params)
   } else {
       throw new Error (exchange.id + ' does not have the fetchTransactions method')
   }

.. code-block:: Python

   # Python
   # fetch_transactions(code = None, since = None, limit = None, params = {})

   if exchange.has['fetchTransactions']:
       transactions = exchange.fetch_transactions(code, since, limit, params)
   else:
       raise Exception (exchange.id + ' does not have the fetch_transactions method')

.. code-block:: PHP

   // PHP
   // fetch_transactions ($code = null, $since = null, $limit = null, $params = {})

   if ($exchange->has['fetchTransactions']) {
       $transactions = $exchange->fetch_transactions ($code, $since, $limit, $params);
   } else {
       throw new Exception ($exchange->id . ' does not have the fetch_transactions method');
   }

Deposit Addresses
-----------------

The address for depositing can be either an already existing address that was created previously with the exchange or it can be created upon request. In order to see which of the two methods are supported, check the ``exchange.has['fetchDepositAddress']`` and ``exchange.has['createDepositAddress']`` properties.

.. code-block:: JavaScript

   fetchDepositAddress (code, params = {})
   createDepositAddress (code, params = {})

Parameters


 * **code** (String) *required* Unified CCXT currency code (e.g. ``"USDT"``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * an :ref:`address structure <address structure>`

----

Some exchanges may also have a method for fetching multiple deposit addresses at once or all of them at once.

.. code-block:: JavaScript

   fetchDepositAddresses (codes = undefined, params = {})

Parameters


 * **code** ([String]) Array of unified CCXT currency codes. May or may not be required depending on the exchange (e.g. ``["USDT", "BTC"]``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * an array of :ref:`address structures <address structure>`

.. code-block:: Javascript

   fetchDepositAddressesByNetwork (code, params = {})

Parameters


 * **code** (String) *required* Unified CCXT currency code (e.g. ``"USDT"``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * an array of :ref:`address structures <address structure>`

Address structure
~~~~~~~~~~~~~~~~~

The address structures returned from ``fetchDepositAddress``\ , ``fetchDepositAddresses``\ , ``fetchDepositAddressesByNetwork`` and ``createDepositAddress`` look like this:

.. code-block:: JavaScript

   {
       'currency': currency, // currency code
       'network': network,   // a list of deposit/withdraw networks, ERC20, TRC20, BSC20 (see below)
       'address': address,   // address in terms of requested currency
       'tag': tag,           // tag / memo / paymentId for particular currencies (XRP, XMR, ...)
       'info': response,     // raw unparsed data as returned from the exchange
   }

With certain currencies, like AEON, BTS, GXS, NXT, SBD, STEEM, STR, XEM, XLM, XMR, XRP, an additional argument ``tag`` is usually required by exchanges. Other currencies will have the ``tag`` set to ``undefined / None / null``. The tag is a memo or a message or a payment id that is attached to a withdrawal transaction. The tag is mandatory for those currencies and it identifies the recipient user account.

Be careful when specifying the ``tag`` and the ``address``. The ``tag`` is **NOT an arbitrary user-defined string** of your choice! You cannot send user messages and comments in the ``tag``. The purpose of the ``tag`` field is to address your wallet properly, so it must be correct. You should only use the ``tag`` received from the exchange you're working with, otherwise your transaction might never arrive to its destination.

 **The ``network`` field is relatively new, it may be ``undefined / None / null`` or missing entirely in certain cases (with some exchanges), but will be added everywhere eventually. It is still in the process of unification.**

Transfers
---------

The ``transfer`` method makes internal transfers of funds between accounts on the same exchange. This can include subaccounts or accounts of different types (\ ``spot``\ , ``margin``\ , ``future``\ , ...). If an exchange is separated on CCXT into a spot and futures class (e.g. ``binanceusdm``\ , ``kucoinfutures``\ , ...), then the method ``transferIn`` may be available to transfer funds into the futures account, and the method ``transferOut`` may be available to transfer funds out of the futures account

.. code-block:: Javascript

   transfer (code, amount, fromAccount, toAccount, params = {})

Parameters


 * **code** (String) Unified CCXT currency code (e.g. ``"USDT"``\ )
 * **amount** (Float) The amount of currency to transfer (e.g. ``10.5``\ )
 * **fromAccount** (String) The account to transfer funds from.
 * **toAccount** (String) The account to transfer funds to.
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )
 * **params.symbol** (String) Market symbol when transfering to or from a margin account (e.g. ``'BTC/USDT'``\ )

Account Types
^^^^^^^^^^^^^

``fromAccount`` and ``toAccount`` can accept the exchange account id or one of the following unified values:


 * ``funding`` *for some exchanges ``funding`` and ``spot`` are the same account*
 * ``main`` *for some exchanges that allow for subaccounts*
 * ``spot``
 * ``margin``
 * ``future``
 * ``swap``
 * ``lending``

You can retrieve all the account types by selecting the keys from `exchange.options['accountsByType']

Some exchanges allow transfers to email addresses, phone numbers or to other users by user id.

Returns


 * A :ref:`transfer structure <transfer structure>`

.. code-block:: Javascript

   transferIn (code, amount, params = {})
   transferOut (code, amount, params = {})

Parameters


 * **code** (String) Unified CCXT currency code (e.g. ``"USDT"``\ )
 * **amount** (Float) The amount of currency to transfer (e.g. ``10.5``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * A :ref:`transfer structure <transfer structure>`

.. code-block:: Javascript

   fetchTransfers (code = undefined, since = undefined, limit = undefined, params = {})

Parameters


 * **code** (String) Unified CCXT currency code (e.g. ``"USDT"``\ )
 * **since** (Integer) Timestamp (ms) of the earliest time to retrieve transfers for (e.g. ``1646940314000``\ )
 * **limit** (Integer) The number of :ref:`transfer structures <transfer structure>` to retrieve (e.g. ``5``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * An array of :ref:`transfer structures <transfer structure>`

.. code-block:: Javascript

   fetchTransfer (id, since = undefined, limit = undefined, params = {})

Parameters


 * **id** (String) tranfer id (e.g. ``"12345"``\ )
 * **since** (Integer) Timestamp (ms) of the earliest time to retrieve transfers for (e.g. ``1646940314000``\ )
 * **limit** (Integer) The number of :ref:`transfer structures <transfer structure>` to retrieve (e.g. ``5``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * A :ref:`transfer structure <transfer structure>`

Transfer Structure
^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   {
       info: { ... },
       id: "93920432048",
       timestamp: 1646764072000,
       datetime: "2022-03-08T18:27:52.000Z",
       currency: "USDT",
       amount: 11.31,
       fromAccount: "spot",
       toAccount: "future",
       status: "ok"
   }

Fees
----

 **This section of the Unified CCXT API is under development.**

Fees are often grouped into two categories:


 * Trading fees. Trading fee is the amount payable to the exchange, usually a percentage of volume traded (filled)).
 * Transaction fees. The amount payable to the exchange upon depositing and withdrawing as well as the underlying crypto transaction fees (tx fees).

Because the fee structure can depend on the actual volume of currencies traded by the user, the fees can be account-specific. Methods to work with account-specific fees:

.. code-block:: Javascript

   fetchFees (params = {})
   fetchTradingFee (symbol, params = {})
   fetchTradingFees (params = {})
   fetchTransactionFee (code, params = {})
   fetchTransactionFees (codes  = undefined, params = {})

The fee methods will return a unified fee structure, which is often present with orders and trades as well. The fee structure is a common format for representing the fee info throughout the library. Fee structures are usually indexed by market or currency.

Because this is still a work in progress, some or all of methods and info described in this section may be missing with this or that exchange.

 **DO NOT use the ``.fees`` property of the exchange instance as most often it contains the predefined/hardcoded info. Actual fees should only be accessed from markets and currencies.**

``fetchFees`` will automatically call both ``fetchTradingFees`` and ``fetchTransactionFees`` to get all the fee information. You can call ``fetchTradingFees`` or ``fetchTransactionFees`` for more precise control over what endpoint on the exchange is requested.

Fee Structure
^^^^^^^^^^^^^

Orders, private trades, transactions and ledger entries may define the following info in their ``fee`` field:

.. code-block:: Javascript

   {
       'currency': 'BTC', // the unified fee currency code
       'rate': percentage, // the fee rate, 0.05% = 0.0005, 1% = 0.01, ...
       'cost': feePaid, // the fee cost (amount * fee rate)
   }

Fee Schedule
^^^^^^^^^^^^

.. code-block:: Javascript

   fetchFees (params = {})

.. code-block:: Javascript

   {
       'funding': {
           'withdraw': {
               'BTC': 0.00001,
               'ETH': 0.001,
               'LTC': 0.0003,
           },
           'deposit': {
               'BTC': 0,
           },
           'info': { ... },
       },
       'trading': {
           'ETH/BTC': {
               'maker': 0.001,
               'taker': 0.002,
               'info': { ... },
               'symbol': 'ETH/BTC',
           },
           'LTC/BTC': {
               'maker': 0.001,
               'taker': 0.002,
               'info': { ... },
               'symbol': 'LTC/BTC',
           },
       },
   }

Trading Fees
^^^^^^^^^^^^

Trading fees are properties of markets. Most often trading fees are loaded into the markets by the ``fetchMarkets`` call. Sometimes, however, the exchanges serve fees from different endpoints.

The ``calculateFee`` method can be used to precalculate trading fees that will be paid. **WARNING! This method is experimental, unstable and may produce incorrect results in certain cases.** You should only use it with caution. Actual fees may be different from the values returned from ``calculateFee``\ , this is just for precalculation.  Do not rely on precalculated values, because market conditions change frequently. It is difficult to know in advance whether your order will be a market taker or maker.

.. code-block:: Javascript

       calculateFee (symbol, type, side, amount, price, takerOrMaker = 'taker', params = {})

The ``calculateFee`` method will return a unified fee structure with precalculated fees for an order with specified params.

Accessing trading fee rates should be done via the ``.markets`` property, like so:

.. code-block:: Javascript

   exchange.markets['ETH/BTC']['taker'] // taker fee rate for ETH/BTC
   exchange.markets['BTC/USD']['maker'] // maker fee rate for BTC/USD

The markets stored under the ``.markets`` property may contain additional fee related information:

.. code-block:: Javascript

   {
       'taker': 0.002,   // taker fee rate, 0.002 = 0.2%
       'maker': 0.0016,  // maker fee rate, 0.0016 = 0.16%
       'percentage': true, // whether the taker and maker fee rate is a multiplier or a fixed flat amount
       'tierBased': false, // whether the fee depends on your trading tier (your trading volume)

       'tiers': {
           'taker': [
               [0, 0.0026], // tupple (trade volume in USD, taker fee) ordered by increasing volume
               [50000, 0.0024],
               ...
           ],
           'maker': [
               [0, 0.0016], // tupple (trade volume in USD, maker fee) ordered by increasing volume
               [50000, 0.0014],
               ...
           ],
       },
   }

 **WARNING! fee related information is experimental, unstable and may only be partial available or not at all.**

Maker fees are paid when you provide liquidity to the exchange i.e. you *market-make* an order and someone else fills it. Maker fees are usually lower than taker fees. Similarly, taker fees are paid when you *take* liquidity from the exchange and fill someone else's order.

Fees can be negative, this is very common amongst derivative exchanges. A negative fee means the exchange will pay a rebate (reward) to the user for the trading.

Also, some exchanges might not specify fees as percentage of volume, check the ``percentage`` field of the market to be sure.

Trading Fee Schedule
~~~~~~~~~~~~~~~~~~~~

Some exchanges have an endpoint for fetching the trading fee schedule, this is mapped to the unified methods ``fetchTradingFees``\ , and ``fetchTradingFee``

.. code-block:: Javascript

   fetchTradingFee (symbol, params = {})

Parameters


 * **symbol** (String) *required* Unified market symbol (e.g. ``"BTC/USDT"``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"currency": "quote"}``\ )

Returns


 * A :ref:`trading fee structure <trading fee structure>`

.. code-block:: Javascript

   fetchTradingFees (params = {})

Parameters


 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"currency": "quote"}``\ )

Returns


 * An array of :ref:`trading fee structures <trading fee structure>`

Trading Fee Structure
"""""""""""""""""""""

.. code-block:: JavaScript

   {
       'ETH/BTC': {
           'maker': 0.001,
           'taker': 0.002,
           'info': { ... },
           'symbol': 'ETH/BTC',
       },
       'LTC/BTC': {
           'maker': 0.001,
           'taker': 0.002,
           'info': { ... },
           'symbol': 'LTC/BTC',
       },
   }

Transaction Fees
^^^^^^^^^^^^^^^^

Transaction fees are properties of currencies (account balance).

Accessing transaction fee rates should be done via the ``.currencies`` property. This aspect is not unified yet and is subject to change.

.. code-block:: Javascript

   exchange.currencies['ETH']['fee'] // tx/withdrawal fee rate for ETH
   exchange.currencies['BTC']['fee'] // tx/withdrawal fee rate for BTC

Transaction Fee Schedule
~~~~~~~~~~~~~~~~~~~~~~~~

Some exchanges have an endpoint for fetching the transaction fee schedule, this is mapped to the unified methods


 * ``fetchTransactionFee ()`` for a single transaction fee schedule
 * ``fetchTransactionFees ()`` for all transaction fee schedules

.. code-block:: Javascript

   fetchTransactionFee (code, params = {})

Parameters


 * **code** (String) *required* Unified CCXT currency code, required (e.g. ``"USDT"``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"type": "deposit"}``\ )
 * **params.network** (String) Specify unified CCXT network (e.g. ``{"network": "TRC20"}``\ )

Returns


 * A :ref:`transaction fee structure <transaction fee structure>`

.. code-block:: Javascript

   fetchTransactionFees (codes = undefined, params = {})

Parameters


 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"type": "deposit"}``\ )

Returns


 * An array of :ref:`transaction fee structures <transaction fee structure>`

Transaction Fee Structure
"""""""""""""""""""""""""

.. code-block:: JavaScript

   {
       'withdraw': {
           'BTC': 0.00001,
           'ETH': 0.001,
           'LTC': 0.0003,
       },
       'deposit': {
           'BTC': 0,
       },
       'info': { ... },
   }

Borrow Interest
---------------


 * margin only

To trade with leverage in spot or margin markets, currency must be borrowed as a loan. This borrowed currency must be payed back with interest. To obtain the amount of interest that has accrued you can use the ``fetchBorrowInterest`` method

.. code-block:: JavaScript

   fetchBorrowInterest (code = undefined, symbol = undefined, since = undefined, limit = undefined, params = {})

Parameters


 * **code** (String) The unified currency code for the currency of the interest (e.g. ``"USDT"``\ )
 * **symbol** (String) The market symbol of an isolated margin market, if undefined, the interest for cross margin markets is returned (e.g. ``"BTC/USDT:USDT"``\ )
 * **since** (Integer) Timestamp (ms) of the earliest time to receive interest records for (e.g. ``1646940314000``\ )
 * **limit** (Integer) The number of :ref:`borrow interest structures <borrow interest structure>` to retrieve (e.g. ``5``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * An array of :ref:`borrow interest structures <borrow interest structure>`

Borrow Interest Structure
^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   {
       account: 'BTC/USDT',                    // The market that the interest was accrued in
       currency: 'USDT',                       // The currency of the interest
       interest: 0.00004842,                   // The amount of interest that was charged
       interestRate: 0.0002,                   // The borrow interest rate
       amountBorrowed: 5.81,                   // The amount of currency that was borrowed
       timestamp: 1648699200000,               // The timestamp that the interest was charged
       datetime: '2022-03-31T04:00:00.000Z',   // The datetime that the interest was charged
       info: { ... }                           // Unparsed exchange response
   }

Borrow and Repay Margin
-----------------------

 *margin only*

To borrow and repay currency as a margin loan use ``borrowMargin`` and ``repayMargin``.

.. code-block:: Javascript

   borrowMargin (code, amount, symbol = undefined, params = {})
   repayMargin (code, amount, symbol = undefined, params = {})

Parameters


 * **code** (String) *required* The unified currency code for the currency to be borrowed or repaid (e.g. ``"USDT"``\ )
 * **amount** (Float) *required* The amount of margin to borrow or repay (e.g. ``20.92``\ )
 * **symbol** (String) The unified CCXT market symbol of an isolated margin market (e.g. ``"BTC/USDT"``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"rate": 0.002}``\ )

Returns


 * A :ref:`margin loan structure <margin loan structure>`

Margin Loan Structure
^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   {
       id: '1234323',                          // integer, the transaction id
       currency: 'USDT',                       // string, the currency that is borrowed or repaid
       amount: 5.81,                           // float, the amount of currency that was borrowed or repaid
       symbol: 'BTC/USDT:USDT',                // string, unified market symbol
       timestamp: 1648699200000,               // integer, the timestamp of when the transaction was made
       datetime: '2022-03-31T04:00:00.000Z',   // string, the datetime of when the transaction was made
       info: { ... }                           // Unparsed exchange response
   }

Margin
------

 *margin and contract only*

To increase, reduce or set your margin balance (collateral) in an open leveraged position, use ``addMargin``\ , ``reduceMargin`` and ``setMargin`` respectively. This is kind of like adjusting the amount of leverage you're using with a position that's already open.

Some scenarios to use these methods include


 * if the trade is going against you, you can add margin to, reducing the risk of liquidation
 * if your trade is going well you can reduce your position's margin balance and take profits

.. code-block:: Javascript

   addMargin (symbol, amount, params = {})
   reduceMargin (symbol, amount, params = {})
   setMargin (symbol, amount, params = {})

Parameters


 * **symbol** (String) *required* Unified CCXT market symbol (e.g. ``"BTC/USDT:USDT"``\ )
 * **amount** (String) *required* Amount of margin to add or reduce (e.g. ``20``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"leverage": 5}``\ )

Returns


 * a :ref:`margin structure <margin structure>`

Margin Structure
^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   {
       info: { ... },
       type: 'add', // 'add', 'reduce', 'set'
       amount: 1, // amount added, reduced, or set
       total: 2,  // total margin or undefined if not specified by the exchange
       code: 'USDT',
       symbol: 'XRP/USDT:USDT',
       status: 'ok'
   }

Margin Mode
-----------

 *margin and contract only*

Updates the type of margin used to be either


 * ``cross`` One account is used to share collateral between markets. Margin is taken from total account balance to avoid liquidation when needed.
 * ``isolated`` Each market, keeps collateral in a separate account

.. code-block:: Javascript

   setMarginMode (marginMode, symbol = undefined, params = {})

Parameters


 * **marginMode** (String) *required* the type of margin used
    **Unified margin types:**

  * ``"cross"``
  * ``"isolated"``

 * **symbol** (String) Unified CCXT market symbol (e.g. ``"BTC/USDT:USDT"``\ ) *required* on most exchanges. Is not required when the margin mode is not specific to a market
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"leverage": 5}``\ )

Returns


 * response from the exchange

Exchanges without setMarginMode
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Common reasons for why an exchange might have

.. code-block:: JavaScript

   exchange.has['setMarginMode'] == false

include


 * the exchange does not offer leveraged trading
 * the exchange only offers one of ``cross`` or ``isolated`` margin modes, but does not offer both
 * margin mode must be set using an exchange specific parameter within ``params`` when using ``createOrder``
  ### Notes on suppressed errors for setMarginMode

Some exchange apis return an error response when a request is sent to set the margin mode to the mode that it is already set to (e.g. Sending a request to set the margin mode to ``cross`` for the market ``BTC/USDT:USDT`` when the account already has ``BTC/USDT:USDT`` set to use cross margin). CCXT doesn't see this as an error because the end result is what the user wanted, so the error is suppressed and the error result is returned as an object.

e.g.

.. code-block:: JavaScript

   { code: -4046, msg: 'No need to change margin type.' }

Leverage
--------

 *margin and contract only*

.. code-block:: Javascript

   setLeverage (leverage, symbol = undefined, params = {})

Parameters


 * **leverage** (Integer) *required* The desired leverage
 * **symbol** (String) Unified CCXT market symbol (e.g. ``"BTC/USDT:USDT"``\ ) *required* on most exchanges. Is not required when leverage is not specific to a market (e.g. Not required on **FTX** because leverage is set for the account and not per market)
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"marginMode": "cross"}``\ )

Returns


 * response from the exchange

Contract trading
----------------

This can include futures with a set expiry date, perpetual swaps with funding payments, and inverse futures or swaps.
Information about the positions can be served from different endpoints depending on the exchange.
In the case that there are multiple endpoints serving different types of derivatives CCXT will default to just loading the "linear" (as oppose to the "inverse") contracts or the "swap" (as opposed to the "future") contracts.

Positions
---------

 *contract only*

To get information about positions currently held in contract markets, use


 * fetchPosition ()            // for a single market
 * fetchPositions ()           // for all positions
 * fetchAccountPositions ()    // TODO

.. code-block:: JavaScript

   fetchPosition (symbol, params = {})                         // for a single market

Parameters


 * **symbol** (String) *required* Unified CCXT market symbol (e.g. ``"BTC/USDT:USDT"``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * A :ref:`position structure <position structure>`

.. code-block:: JavaScript

   fetchPositions (symbols = undefined, params = {})
   fetchAccountPositions (symbols = undefined, params = {})

Parameters


 * **symbols** ([String]) Unified CCXT market symbols, do not set to retrieve all positions (e.g. ``["BTC/USDT:USDT"]``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * An array of :ref:`position structures <position structure>`

Position Structure
^^^^^^^^^^^^^^^^^^

.. code-block:: Javascript

   {
      'info': { ... },             // json response returned from the exchange as is
      'id': '1234323',             // string, position id to reference the position, similar to an order id
      'symbol': 'BTC/USD',         // uppercase string literal of a pair of currencies
      'timestamp': 1607723554607,  // integer unix time since 1st Jan 1970 in milliseconds
      'datetime': '2020-12-11T21:52:34.607Z',  // ISO8601 representation of the unix time above
      'isolated': true,            // boolean, whether or not the position is isolated, as opposed to cross where margin is added automatically
      'hedged': false,             // boolean, whether or not the position is hedged, i.e. if trading in the opposite direction will close this position or make a new one
      'side': 'long',              // string, long or short
      'contracts': 5,              // float, number of contracts bought, aka the amount or size of the position
      'contractSize': 100,         // float, the size of one contract in quote units
      'entryPrice': 20000,         // float, the average entry price of the position
      'markPrice': 20050,          // float, a price that is used for funding calculations
      'notional': 100000,          // float, the value of the position in the settlement currency
      'leverage': 100,             // float, the leverage of the position, related to how many contracts you can buy with a given amount of collateral
      'collateral': 5300,          // float, the maximum amount of collateral that can be lost, affected by pnl
      'initialMargin': 5000,       // float, the amount of collateral that is locked up in this position
      'maintenanceMargin': 1000,   // float, the mininum amount of collateral needed to avoid being liquidated
      'initialMarginPercentage': 0.05,      // float, the initialMargin as a percentage of the notional
      'maintenanceMarginPercentage': 0.01,  // float, the maintenanceMargin as a percentage of the notional
      'unrealizedPnl': 300,        // float, the difference between the market price and the entry price times the number of contracts, can be negative
      'liquidationPrice': 19850,   // float, the price at which collateral becomes less than maintenanceMargin
      'marginMode': 'cross',       // string, can be cross or isolated
      'percentage': 3.32,          // float, represents unrealizedPnl / initialMargin * 100
   }

Positions allow you to borrow money from an exchange to go long or short on an market. Some exchanges require you to pay a funding fee to keep the position open.

When you go long on a position you are betting that the price will be higher in the future and that the price will never be less than the ``liquidationPrice``.

As the price of the underlying index changes so does the unrealisedPnl and as a consequence the amount of collateral you have left in the position (since you can only close it at market price or worse). At some price you will have zero collateral left, this is called the "bust" or "zero" price. Beyond this point, if the price goes in the opposite direction far enough, the collateral of the position will drop below the ``maintenanceMargin``. The maintenanceMargin acts as a safety buffer between your position and negative collateral, a scenario where the exchange incurs losses on your behalf. To protect itself the exchange will swiftly liquidate your position if and when this happens. Even if the price returns back above the liquidationPrice you will not get your money back since the exchange sold all the ``contracts`` you bought at market. In other words the maintenanceMargin is a hidden fee to borrow money.

It is recommended to use the ``maintenanceMargin`` and ``initialMargin`` instead of the ``maintenanceMarginPercentage`` and ``initialMarginPercentage`` since these tend to be more accurate. The maintenanceMargin might be calculated from other factors outside of the maintenanceMarginPercentage including the funding rate and taker fees, for example on `kucoin <https://futures.kucoin.com/contract/detail>`__.

An inverse contract will allow you to go long or short on BTC/USD by putting up BTC as collateral. Our API for inverse contracts is the same as for linear contracts. The amounts in an inverse contracts are quoted as if they were traded USD/BTC, however the price is still quoted terms of BTC/USD.  The formula for the profit and loss of a inverse contract is ``(1/markPrice - 1/price) * contracts``. The profit and loss and collateral will now be quoted in BTC, and the number of contracts are quoted in USD.

Liquidation price
^^^^^^^^^^^^^^^^^

It is the price at which the ``initialMargin + unrealized = collateral = maintenanceMargin``. The price has gone in the opposite direction of your position to the point where the is only maintenanceMargin collateral left and if it goes any further the position will have negative collateral.

.. code-block:: JavaScript

   // if long
   (liquidationPrice - price) * contracts = maintenanceMargin

   // if short
   (price - liquidationPrice) * contracts = maintenanceMargin
   // if inverse long
   (1/liquidationPrice - 1/price) * contracts = maintenanceMargin

   // if inverse short
   (1/price - 1/liquidationPrice) * contracts = maintenanceMargin

Funding History
---------------

 *contract only*

Perpetual swap (also known as perpetual future) contracts maintain a market price that mirrors the price of the asset they are based on because funding fees are exchanged between traders who hold positions in perpetual swap markets.

If the contract is being traded at a price that is higher than the price of the asset they represent, then traders in long positions pay a funding fee to traders in short positions at specific times of day, which encourages more traders to enter short positions prior to these times.

If the contract is being traded at a price that is lower than the price of the asset they represent, then traders in short positions pay a funding fee to traders in long positions at specific times of day, which encourages more traders to enter long positions prior to these times.

These fees are usually exchanged between traders with no commission going to the exchange

The ``fetchFundingHistory`` method can be used to retrieve an accounts history of funding fees paid or received

.. code-block:: Javascript

   fetchFundingHistory (symbol = undefined, since = undefined, limit = undefined, params = {})

Parameters


 * **symbol** (String) Unified CCXT market symbol (e.g. ``"BTC/USDT:USDT"``\ )
 * **since** (Integer) Timestamp (ms) of the earliest time to retrieve funding history for (e.g. ``1646940314000``\ )
 * **limit** (Integer) The number of :ref:`funding history structures <funding history structure>` to retrieve (e.g. ``5``\ )
 * **params** (Dictionary) Parameters specific to the exchange API endpoint (e.g. ``{"endTime": 1645807945000}``\ )

Returns


 * An array of :ref:`funding history structures <funding history structure>`

Funding History Structure
^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: JavaScript

   {
       info: { ... },
       symbol: "XRP/USDT:USDT",
       code: "USDT",
       timestamp: 1646954920000,
       datetime: "2022-03-08T16:00:00.000Z",
       id: "1520286109858180",
       amount: -0.027722
   }

Error Handling
==============



The error handling with CCXT is done with the exception mechanism that is natively available with all languages.

To handle the errors you should add a ``try`` block around the call to a unified method and catch the exceptions like you would normally do with your language:

.. code-block:: JavaScript

   // JavaScript

   // try to call a unified method
   try {
       const response = await exchange.fetchTicker ('ETH/BTC')
       console.log (response)
   } catch (e) {
       // if the exception is thrown, it is "caught" and can be handled here
       // the handling reaction depends on the type of the exception
       // and on the purpose or business logic of your application
       if (e instanceof ccxt.NetworkError) {
           console.log (exchange.id, 'fetchTicker failed due to a network error:', e.message)
           // retry or whatever
       } else if (e instanceof ccxt.ExchangeError) {
           console.log (exchange.id, 'fetchTicker failed due to exchange error:', e.message)
           // retry or whatever
       } else {
           console.log (exchange.id, 'fetchTicker failed with:', e.message)
           // retry or whatever
       }
   }

.. code-block:: Python

   # Python

   # try to call a unified method
   try:
       response = await exchange.fetch_order_book('ETH/BTC')
       print(response)
   except ccxt.NetworkError as e:
       print(exchange.id, 'fetch_order_book failed due to a network error:', str(e))
       # retry or whatever
   except ccxt.ExchangeError as e:
       print(exchange.id, 'fetch_order_book failed due to exchange error:', str(e))
       # retry or whatever
   except Exception as e:
       print(exchange.id, 'fetch_order_book failed with:', str(e))
       # retry or whatever

.. code-block:: PHP

   // PHP

   // try to call a unified method
   try {
       $response = $exchange->fetch_trades('ETH/BTC');
       print_r($response);
   } catch (\ccxt\NetworkError $e) {
       echo $exchange->id . ' fetch_trades failed due to a network error: ' . $e->getMessage () . "\n";
       // retry or whatever
   } catch (\ccxt\ExchangeError $e) {
       echo $exchange->id . ' fetch_trades failed due to exchange error: ' . $e->getMessage () . "\n";
       // retry or whatever
   } catch (Exception $e) {
       echo $exchange->id . ' fetch_trades failed with: ' . $e->getMessage () . "\n";
       // retry or whatever
   }

Exception Hierarchy
-------------------

All exceptions are derived from the base BaseError exception, which, in its turn, is defined in the ccxt library like so:

.. code-block:: JavaScript

   // JavaScript
   class BaseError extends Error {
       constructor () {
           super ()
           // a workaround to make `instanceof BaseError` work in ES5
           this.constructor = BaseError
           this.__proto__   = BaseError.prototype
       }
   }

.. code-block:: Python

   # Python
   class BaseError (Exception):
       pass

.. code-block:: PHP

   // PHP
   class BaseError extends \Exception {}

Below is an outline of exception inheritance hierarchy:

.. code-block:: text

   + BaseError
   |
   +---+ ExchangeError
   |   |
   |   +---+ AuthenticationError
   |   |   |
   |   |   +---+ PermissionDenied
   |   |   |
   |   |   +---+ AccountSuspended
   |   |
   |   +---+ ArgumentsRequired
   |   |
   |   +---+ BadRequest
   |   |   |
   |   |   +---+ BadSymbol
   |   |
   |   +---+ BadResponse
   |   |   |
   |   |   +---+ NullResponse
   |   |
   |   +---+ InsufficientFunds
   |   |
   |   +---+ InvalidAddress
   |   |   |
   |   |   +---+ AddressPending
   |   |
   |   +---+ InvalidOrder
   |   |   |
   |   |   +---+ OrderNotFound
   |   |   |
   |   |   +---+ OrderNotCached
   |   |   |
   |   |   +---+ CancelPending
   |   |   |
   |   |   +---+ OrderImmediatelyFillable
   |   |   |
   |   |   +---+ OrderNotFillable
   |   |   |
   |   |   +---+ DuplicateOrderId
   |   |
   |   +---+ NotSupported
   |
   +---+ NetworkError (recoverable)
       |
       +---+ InvalidNonce
       |
       +---+ RequestTimeout
       |
       +---+ ExchangeNotAvailable
       |   |
       |   +---+ OnMaintenance
       |
       +---+ DDoSProtection
           |
           +---+ RateLimitExceeded

The ``BaseError`` class is a generic error class for all sorts of errors, including accessibility and request/response mismatch. Users should catch this exception at the very least, if no error differentiation is required.

There's two generic families of special cases or subtrees in the error hierarchy, both derived from ``BaseError``\ :


 * ``NetworkError``
 * ``ExchangeError``

A ``NetworkError`` is a non-critical non-breaking error, not really an error in a full sense, but more like a temporary unavailability situation, that could be caused by any condition or by any factor, including maintenance, DDoS protections, and temporary bans. The reason for having a big family of ``NetworkError`` is to group all exceptions that can reappear or disappear upon a later retry or upon a retry from a different location, all the rest being equal (with the same user input, put simply, same order price and amount, same symbol, etc...).

In contrast, the ``ExchangeError`` is a critical error indeed, and it differs from the ``NetworkError`` in a very specific way – if you get an ``ExchangeError`` with your input, then you should always get the same ``ExchangeError`` with that same input.

The distinction between the two families of exceptions is such that one family is recoverable and the other family is unrecoverable. ``NetworkError`` means you can retry later and it can magically go away by itself, so a subsequent retry may succeed and the user may be able to recover from a ``NetworkError`` just by waiting. An ``ExchangeError`` is a fatal error, so, it means, something went bad and it will go bad every time, unless you change the input.

ExchangeError
^^^^^^^^^^^^^

This exception is thrown when an exchange server replies with an error in JSON. Possible reasons:


 * endpoint is switched off by the exchange
 * symbol not found on the exchange
 * required parameter is missing
 * the format of parameters is incorrect
 * an exchange replies with an unclear answer

Other exceptions derived from ``ExchangeError``\ :


 * ``NotSupported``\ : This exception is raised if the endpoint is not offered/not supported by the exchange API.
 * ``AuthenticationError``\ : Raised when an exchange requires one of the API credentials that you've missed to specify, or when there's a mistake in the keypair or an outdated nonce. Most of the time you need ``apiKey`` and ``secret``\ , sometimes you also need ``uid`` and/or ``password``.
 * ``PermissionDenied``\ : Raised when there's no access for specified action or insufficient permissions on the specified ``apiKey``.
 * ``InsufficientFunds``\ : This exception is raised when you don't have enough currency on your account balance to place an order.
 * ``InvalidAddress``\ : This exception is raised upon encountering a bad funding address or a funding address shorter than ``.minFundingAddressLength`` (10 characters by default) in a call to ``fetchDepositAddress``\ , ``createDepositAddress`` or ``withdraw``.
 * ``InvalidOrder``\ : This exception is the base class for all exceptions related to the unified order API.
 * ``OrderNotFound``\ : Raised when you are trying to fetch or cancel a non-existent order.

NetworkError
^^^^^^^^^^^^

All errors related to networking are usually recoverable, meaning that networking problems, traffic congestion, unavailability is usually time-dependent. Making a retry later is usually enough to recover from a NetworkError, but if it doesn't go away, then it may indicate some persistent problem with the exchange or with your connection.

DDoSProtection
~~~~~~~~~~~~~~

This exception is thrown in either of two cases:


 * when Cloudflare or Incapsula rate limiter restrictions are enforced per user or region/location
 * when the exchange restricts user access for requesting the endpoints in question too frequently

RequestTimeout
~~~~~~~~~~~~~~

This exception is raised when the connection with the exchange fails or data is not fully received in a specified amount of time. This is controlled by the ``timeout`` option. When a ``RequestTimeout`` is raised, the user doesn't know the outcome of a request (whether it was accepted by the exchange server or not).

Thus it's advised to handle this type of exception in the following manner:


 * for fetching requests it is safe to retry the call
 * for a request to ``cancelOrder()`` a user is required to retry the same call the second time. A subsequent retry to ``cancelOrder()`` will return one of the following possible results:

  * a request is completed successfully, meaning the order has been properly canceled now
  * an ``OrderNotFound`` exception is raised, which means the order was either already canceled on the first attempt or has been executed (filled and closed) in the meantime between the two attempts.

 * if a request to ``createOrder()`` fails with a ``RequestTimeout`` the user should:

  * call ``fetchOrders()``\ , ``fetchOpenOrders()``\ , ``fetchClosedOrders()`` to check if the request to place the order has succeeded and the order is now open
  * if the order is not ``'open'`` the user should ``fetchBalance()`` to check if the balance has changed since the order was created on the first run and then was filled and closed by the time of the second check.

ExchangeNotAvailable
~~~~~~~~~~~~~~~~~~~~

This type of exception is thrown when the underlying exchange is unreachable.

The ccxt library also throws this error if it detects any of the following keywords in response:


 * ``offline``
 * ``unavailable``
 * ``busy``
 * ``retry``
 * ``wait``
 * ``maintain``
 * ``maintenance``
 * ``maintenancing``

InvalidNonce
~~~~~~~~~~~~

Raised when your nonce is less than the previous nonce used with your keypair, as described in the :ref:`Authentication <authentication>` section. This type of exception is thrown in these cases (in order of precedence for checking):


 * You are not rate-limiting your requests or sending too many of them too often.
 * Your API keys are not fresh and new (have been used with some different software or script already, just always create a new keypair when you add this or that exchange).
 * The same keypair is shared across multiple instances of the exchange class (for example, in a multithreaded environment or in separate processes).
 * Your system clock is out of synch. System time should be synched with UTC in a non-DST timezone at a rate of once every ten minutes or even more frequently because of the clock drifting. **Enabling time synch in Windows is usually not enough!** You have to set it up with the OS Registry (Google *"time synch frequency"* for your OS).

Troubleshooting
===============

In case you experience any difficulty connecting to a particular exchange, do the following in order of precedence:


 * Make sure that you have the most recent version of ccxt.
  Never trust your package installer (whether it is ``npm``\ , ``pip`` or ``composer``\ ), instead always check your **actual (real) runtime version number** by running this code in your environment:
  .. code-block:: JavaScript

     console.log (ccxt.version) // JavaScript

  .. code-block:: Python

     print('CCXT version:', ccxt.__version__)  # Python

  .. code-block:: PHP

     echo "CCXT v." . \ccxt\Exchange::VERSION . "\n"; // PHP

 * Check the `Issues <https://github.com/ccxt/ccxt/issues>`__ for recent updates.
 * Make sure you have :ref:`rate-limiter enabled with ``enableRateLimit: true`` <rate limit>` (either the built-in rate-limiter or your own custom rate-limiter).
 * Turn ``verbose = true`` to get more detail about it!
  .. code-block:: Python

     import ccxt
     exchange = ccxt.binance()
     exchange.load_markets()
     exchange.verbose = True  # enable verbose mode after loading the markets
  Your `code to reproduce the issue + verbose output is required <https://github.com/ccxt/ccxt/wiki/FAQ#what-is-required-to-get-help>`__ in order to get help.
 * Python people can turn on DEBUG logging level with a standard pythonic logger, by adding these two lines to the beginning of their code:
  .. code-block:: Python

     import logging
     logging.basicConfig(level=logging.DEBUG)

 * Use verbose mode to make sure that the used API credentials correspond to the keys you intend to use. Make sure there's no confusion of keypairs.
 * **Try a fresh new keypair if possible.**
 * Read the answers to Frequently Asked Questions: https://github.com/ccxt/ccxt/wiki/FAQ
 * Check the permissions on the keypair with the exchange website!
 * Check your nonce. If you used your API keys with other software, you most likely should :ref:`override your nonce function <overriding the nonce>` to match your previous nonce value. A nonce usually can be easily reset by generating a new unused keypair. If you are getting nonce errors with an existing key, try with a new API key that hasn't been used yet.
 * Check your request rate if you are getting nonce errors. Your private requests should not follow one another quickly. You should not send them one after another in a split second or in short time. The exchange will most likely ban you if you don't make a delay before sending each new request. In other words, you should not hit their rate limit by sending unlimited private requests too frequently. Add a delay to your subsequent requests or enable the built-in rate-limiter, like shown in the long-poller `examples <https://github.com/ccxt/ccxt/tree/master/examples>`__\ , also :ref:`here <order-book--market-depth>`.
 * Read the `docs for your exchange <https://github.com/ccxt/ccxt/wiki/Exchanges>`__ and compare your verbose output to the docs.
 * Check your connectivity with the exchange by accessing it with your browser.
 * Check your connection with the exchange through a proxy. Read the `Proxy <https://github.com/ccxt/ccxt/wiki/Install#proxy>`__ section for more details.
 * Try accesing the exchange from a different computer or a remote server, to see if this is a local or global issue with the exchange.
 * Check if there were any news from the exchange recently regarding downtime for maintenance. Some exchanges go offline for updates regularly (like once a week).
 * Make sure that your system time in sync with the rest of the world's clocks since otherwise you may get invalid nonce errors.

Notes
^^^^^


 * Use the ``verbose = true`` option or instantiate your troublesome exchange with ``new ccxt.exchange ({ 'verbose': true })`` to see the HTTP requests and responses in details. The verbose output will also be of use for us to debug it if you submit an issue on GitHub.
 * Use DEBUG logging in Python!
 * As written above, some exchanges are not available in certain countries. You should use a proxy or get a server somewhere closer to the exchange.
 * If you are getting authentication errors or *'invalid keys'* errors, those are most likely due to a nonce issue.
 * Some exchanges do not state it clearly if they fail to authenticate your request. In those circumstances they might respond with an exotic error code, like HTTP 502 Bad Gateway Error or something that's even less related to the actual cause of the error.