Databento

NautilusTrader includes an adapter for the Databento API and Databento Binary Encoding (DBN) format data. Databento is a market data provider only. The adapter does not include an execution client, but you can pair it with a sandbox for simulated execution. You can also match Databento data with Interactive Brokers execution, or calculate traditional asset class signals for crypto trading.

The adapter supports:

• Loading historical data from DBN files and decoding to Nautilus objects for backtesting or catalog storage.
• Requesting historical data decoded to Nautilus objects for live trading and backtesting.
• Subscribing to real-time data feeds decoded to Nautilus objects for live trading and sandbox environments.

:::tip Databento offers 125 USD in free data credits (historical only) for new sign-ups.

With careful requests, this covers testing and evaluation. Check the /metadata.get_cost endpoint before requesting data. :::

Overview

The adapter uses the databento-rs crate, Databento's official Rust client library.

:::info No separate databento installation is needed. The adapter compiles as a static library and links automatically during the build. :::

The following adapter classes are available:

• DatabentoDataLoader: Loads DBN data from files.
• DatabentoInstrumentProvider: Fetches latest or historical instrument definitions via the Databento HTTP API.
• DatabentoHistoricalClient: Fetches historical market data via the Databento HTTP API.
• DatabentoLiveClient: Subscribes to real-time data feeds via Databento's raw TCP API.
• DatabentoDataClient: LiveMarketDataClient implementation for live trading nodes.

:::info Most users configure a live trading node (covered below) and do not work with these components directly. :::

Examples

Live example scripts are available here.

Databento documentation

See the Databento new users guide. Refer to it alongside this integration guide.

Databento Binary Encoding (DBN)

Databento Binary Encoding (DBN) is a fast message encoding and storage format for normalized market data. The DBN specification includes a self-describing metadata header and a fixed set of struct definitions that standardize how market data is normalized.

The adapter decodes DBN data to Nautilus objects. The same Rust decoder handles:

• Loading and decoding DBN files from disk.
• Decoding historical and live data in real time.

Supported schemas

The following Databento schemas are supported by NautilusTrader:

Schema considerations

• TBBO and TCBBO: Trade-sampled feeds that pair every trade with the BBO immediately before the trade's effect (TBBO per-venue, TCBBO consolidated). Use when you need trades aligned with contemporaneous quotes without managing two streams.
• MBP-1 and CMBP-1 (L1): Event-level updates; emit trades only on trade events. Choose for a complete top-of-book event tape. For quote+trade alignment, prefer TBBO/TCBBO; otherwise use TRADES.
• MBP-10 (L2): Top 10 levels with trades. Lighter than MBO for depth-aware strategies. Includes orders per level.
• MBO (L3): Per-order events for queue position modeling and exact book reconstruction. Highest volume/cost; start at node initialization for proper replay context.
• BBO_1S/BBO_1M and CBBO_1S/CBBO_1M: Sampled top-of-book quotes at fixed intervals (1s/1m), no trades. Good for monitoring, spreads, and low-cost signals. Not suited for microstructure work.
• TRADES: Trades only. Pair with MBP-1 (include_trades=True) or use TBBO/TCBBO for quote context with trades.
• OHLCV_ (incl. OHLCV_EOD): Aggregated bars from trades. Use for higher-timeframe analytics. Set bars_timestamp_on_close=True for close timestamps.
• Imbalance / Statistics / Status: Venue operational data; subscribe via subscribe_data with a DataType carrying instrument_id metadata.

:::tip Consolidated schemas (CMBP_1, CBBO_1S, CBBO_1M, TCBBO) aggregate data across multiple venues. Useful for cross-venue analysis. :::

:::info See also the Databento Schemas and data formats guide. :::

Schema selection for live subscriptions

Nautilus subscription methods map to Databento schemas as follows:

:::note The examples below assume a Strategy or Actor context where self has subscription methods. Import the required types:

from nautilus_trader.adapters.databento import DATABENTO_CLIENT_ID
from nautilus_trader.model import BarType
from nautilus_trader.model.enums import BookType
from nautilus_trader.model.identifiers import InstrumentId

:::

Quote subscriptions (MBP / L1)

# Default MBP-1 quotes (may include trades)
self.subscribe_quote_ticks(instrument_id, client_id=DATABENTO_CLIENT_ID)

# Explicit MBP-1 schema
self.subscribe_quote_ticks(
    instrument_id=instrument_id,
    params={"schema": "mbp-1"},
    client_id=DATABENTO_CLIENT_ID,
)

# 1-second BBO snapshots (quotes only, no trades)
self.subscribe_quote_ticks(
    instrument_id=instrument_id,
    params={"schema": "bbo-1s"},
    client_id=DATABENTO_CLIENT_ID,
)

# Consolidated quotes across venues
self.subscribe_quote_ticks(
    instrument_id=instrument_id,
    params={"schema": "cbbo-1s"},  # or "cmbp-1" for consolidated MBP
    client_id=DATABENTO_CLIENT_ID,
)

# Trade-sampled BBO (includes both quotes AND trades)
self.subscribe_quote_ticks(
    instrument_id=instrument_id,
    params={"schema": "tbbo"},  # Will receive both QuoteTick and TradeTick onto the message bus
    client_id=DATABENTO_CLIENT_ID,
)

Trade subscriptions

# Trade ticks only
self.subscribe_trade_ticks(instrument_id, client_id=DATABENTO_CLIENT_ID)

# Trades from MBP-1 feed (only when trade events occur)
self.subscribe_trade_ticks(
    instrument_id=instrument_id,
    params={"schema": "mbp-1"},
    client_id=DATABENTO_CLIENT_ID,
)

# Trade-sampled data (includes quotes at trade time)
self.subscribe_trade_ticks(
    instrument_id=instrument_id,
    params={"schema": "tbbo"},  # Also provides quotes at trade events
    client_id=DATABENTO_CLIENT_ID,
)

Order book depth subscriptions (MBP / L2)

# Subscribe to top 10 levels of market depth
self.subscribe_order_book_depth(
    instrument_id=instrument_id,
    depth=10  # MBP-10 schema is automatically selected
)

# The depth parameter must be 10 for Databento
# This will receive OrderBookDepth10 updates

Order book deltas subscriptions (MBO / L3)

# Subscribe to full order book updates (market by order)
self.subscribe_order_book_deltas(
    instrument_id=instrument_id,
    book_type=BookType.L3_MBO  # Uses MBO schema
)

# Note: MBO subscriptions must be made at node startup for Databento
# to ensure proper replay from session start

Bar subscriptions

# Subscribe to 1-minute bars (automatically uses ohlcv-1m schema)
self.subscribe_bars(
    bar_type=BarType.from_str(f"{instrument_id}-1-MINUTE-LAST-EXTERNAL")
)

# Subscribe to 1-second bars (automatically uses ohlcv-1s schema)
self.subscribe_bars(
    bar_type=BarType.from_str(f"{instrument_id}-1-SECOND-LAST-EXTERNAL")
)

# Subscribe to hourly bars (automatically uses ohlcv-1h schema)
self.subscribe_bars(
    bar_type=BarType.from_str(f"{instrument_id}-1-HOUR-LAST-EXTERNAL")
)

# Subscribe to daily bars (automatically uses ohlcv-1d schema)
self.subscribe_bars(
    bar_type=BarType.from_str(f"{instrument_id}-1-DAY-LAST-EXTERNAL")
)

# Subscribe to daily bars with end-of-day schema (only valid for DAY aggregation)
self.subscribe_bars(
    bar_type=BarType.from_str(f"{instrument_id}-1-DAY-LAST-EXTERNAL"),
    params={"schema": "ohlcv-eod"},  # Override to use end-of-day bars
)

Custom data type subscriptions

Imbalance, statistics, and status data require the generic subscribe_data method:

from nautilus_trader.adapters.databento import DATABENTO_CLIENT_ID
from nautilus_trader.adapters.databento import DatabentoImbalance
from nautilus_trader.adapters.databento import DatabentoStatistics
from nautilus_trader.model import DataType

# Subscribe to imbalance data
self.subscribe_data(
    data_type=DataType(DatabentoImbalance, metadata={"instrument_id": instrument_id}),
    client_id=DATABENTO_CLIENT_ID,
)

# Subscribe to statistics data
self.subscribe_data(
    data_type=DataType(DatabentoStatistics, metadata={"instrument_id": instrument_id}),
    client_id=DATABENTO_CLIENT_ID,
)

# Subscribe to instrument status updates
from nautilus_trader.model.data import InstrumentStatus
self.subscribe_data(
    data_type=DataType(InstrumentStatus, metadata={"instrument_id": instrument_id}),
    client_id=DATABENTO_CLIENT_ID,
)

Instrument IDs and symbology

Databento market data includes an instrument_id field: an integer assigned by the source venue or by Databento during normalization. This differs from the Nautilus InstrumentId, a string of symbol + venue separated by a period: "{symbol}.{venue}".

The decoder maps the Databento raw_symbol to the Nautilus symbol and uses an ISO 10383 MIC (Market Identifier Code) from the definition message for the Nautilus venue.

Databento identifies datasets with a dataset ID, separate from venue identifiers. See Databento dataset naming conventions for details.

For CME Globex MDP 3.0 (GLBX.MDP3), these exchanges group under the GLBX venue. The instrument's exchange field determines the mapping:

• CBCM: XCME-XCBT inter-exchange spread
• NYUM: XNYM-DUMX inter-exchange spread
• XCBT: Chicago Board of Trade (CBOT)
• XCEC: Commodities Exchange Center (COMEX)
• XCME: Chicago Mercantile Exchange (CME)
• XFXS: CME FX Link spread
• XNYM: New York Mercantile Exchange (NYMEX)

:::info Other venue MICs are in the venue field of responses from the metadata.list_publishers endpoint. :::

Timestamps

Databento data includes these timestamp fields:

• ts_event: Matching-engine-received timestamp in nanoseconds since the UNIX epoch.
• ts_in_delta: Matching-engine-sending timestamp in nanoseconds before ts_recv.
• ts_recv: Capture-server-received timestamp in nanoseconds since the UNIX epoch.
• ts_out: Databento sending timestamp.

Nautilus data requires at least two timestamps (per the Data contract):

• ts_event: UNIX timestamp (nanoseconds) when the data event occurred.
• ts_init: UNIX timestamp (nanoseconds) when the data instance was created.

The decoder maps Databento ts_recv to Nautilus ts_event. This timestamp is more reliable and monotonically increases per instrument. The exceptions are DatabentoImbalance and DatabentoStatistics, which carry all timestamp fields since they are adapter-specific types.

:::info See the following Databento docs for further information:

• Databento standards and conventions - timestamps
• Databento timestamping guide

:::

Data types

This section covers Databento schema to Nautilus data type mapping.

:::info See Databento schemas and data formats. :::

Instrument definitions

Databento uses a single schema for all instrument classes. The decoder maps each to the appropriate Nautilus Instrument type.

Price precision

Databento raw prices are fixed-point integers scaled by 1e-9. The adapter derives price precision from the instrument's tick size in the definition message.

For live feeds, the feed handler maintains a per-instrument precision map populated from InstrumentDefMsg records as they arrive. Market data handlers look up precision from this map. Without a prior definition, precision falls back to 2 (USD default).

Instrument definitions must arrive before market data for correct precision on instruments with non-standard tick sizes (e.g., treasury futures with fractional ticks like 1/256). Subscribe to DEFINITION schema for your instruments before or alongside market data subscriptions.

For historical and file-based loading, pass an explicit price_precision parameter to override the default.

:::tip The Python adapter automatically subscribes to instrument definitions before market data, so the precision map populates without extra configuration. For direct Rust client usage, subscribe to DEFINITION schema before market data. :::

MBO (market by order)

MBO is the highest granularity data from Databento, representing full order book depth. Some messages include trade data. The decoder produces an OrderBookDelta and optionally a TradeTick.

The live client buffers MBO messages until it sees an F_LAST flag, then passes an OrderBookDeltas container to the handler.

The client also buffers order book snapshots into OrderBookDeltas during the replay startup sequence.

MBP-1 (market by price, top-of-book)

MBP-1 represents top-of-book quotes and trades. Some messages carry trade data. The decoder produces a QuoteTick and also a TradeTick when the message is a trade.

TBBO and TCBBO (top-of-book with trades)

TBBO and TCBBO provide both quote and trade data in each message. Both schemas emit QuoteTick and TradeTick per message, more efficient than separate quote and trade subscriptions. TCBBO provides consolidated data across venues.

Trade ID derivation (CMBP1 / TCBBO)

The CMBP1 and TCBBO schemas do not publish a native trade identifier. The decoder derives a deterministic TradeId by FNV-1a hashing the instrument ID, ts_event, ts_recv, price, size, and aggressor side of the trade. The same venue event yields the same trade ID across replays, so downstream dedup stays intact. Two logically distinct trades with identical fields collide; this matches the venue's inability to distinguish them.

OHLCV (bar aggregates)

Databento timestamps bar messages at the open of the interval. The decoder normalizes ts_event to the bar close (original ts_event + interval).

Imbalance & Statistics

The imbalance and statistics schemas have no built-in Nautilus equivalents. The adapter defines DatabentoImbalance and DatabentoStatistics in Rust.

PyO3 bindings expose these types in Python. Their attributes are PyO3 objects and may not be compatible with methods expecting Cython types. See the API reference for PyO3 to Cython conversion methods.

Convert a PyO3 Price to a Cython Price:

price = Price.from_raw(pyo3_price.raw, pyo3_price.precision)

Requesting and subscribing to these types requires the generic subscribe_data method. Subscribe to imbalance for AAPL.XNAS:

from nautilus_trader.adapters.databento import DATABENTO_CLIENT_ID
from nautilus_trader.adapters.databento import DatabentoImbalance
from nautilus_trader.model import DataType

instrument_id = InstrumentId.from_str("AAPL.XNAS")
self.subscribe_data(
    data_type=DataType(DatabentoImbalance, metadata={"instrument_id": instrument_id}),
    client_id=DATABENTO_CLIENT_ID,
)

Request the previous day's statistics for the ES.FUT parent symbol (all active E-mini S&P 500 futures):

from nautilus_trader.adapters.databento import DATABENTO_CLIENT_ID
from nautilus_trader.adapters.databento import DatabentoStatistics
from nautilus_trader.model import DataType

instrument_id = InstrumentId.from_str("ES.FUT.GLBX")
metadata = {
    "instrument_id": instrument_id,
    "start": "2024-03-06",
}
self.request_data(
    data_type=DataType(DatabentoStatistics, metadata=metadata),
    client_id=DATABENTO_CLIENT_ID,
)

Catalog persistence

Both types support Arrow serialization for catalog storage. The Arrow serializers register automatically when you import the adapter package.

Writing to the catalog

from nautilus_trader.adapters.databento import DatabentoDataLoader
from nautilus_trader.model.identifiers import InstrumentId
from nautilus_trader.persistence.catalog import ParquetDataCatalog

catalog = ParquetDataCatalog.from_env()
loader = DatabentoDataLoader()

imbalances = loader.from_dbn_file(
    path="aapl-imbalance.dbn.zst",
    instrument_id=InstrumentId.from_str("AAPL.XNAS"),
    as_legacy_cython=False,  # Required for Databento-specific types
)

catalog.write_data(imbalances)

Reading from the catalog

from nautilus_trader.adapters.databento import DatabentoImbalance

results = catalog.query(DatabentoImbalance, identifiers=["AAPL.XNAS"])

for imbalance in results:
    print(imbalance.ref_price)  # DatabentoImbalance fields

:::warning Catalog persistence supports writing and querying these types, but streaming them through BacktestNode or BacktestEngine is not yet supported. For backtesting with imbalance or statistics data, query the catalog directly and process the results in your strategy or analysis code. :::

Encoding and decoding in Rust

The nautilus_databento::arrow module provides Arrow record batch encoding and decoding. Requires the arrow feature flag.

use nautilus_databento::arrow::imbalance::{
    decode_imbalance_batch,
    imbalance_to_arrow_record_batch,
};

let batch = imbalance_to_arrow_record_batch(imbalances)?;

let metadata = batch.schema().metadata().clone();
let decoded = decode_imbalance_batch(&metadata, batch)?;

The statistics module follows the same pattern with decode_statistics_batch and statistics_to_arrow_record_batch.

Performance considerations

Two options for backtesting with DBN data:

• Store data as DBN (.dbn.zst) files and decode to Nautilus objects every run.
• Convert DBN files to Nautilus objects once and write to the data catalog (Nautilus Parquet format).

The DBN decoder is optimized Rust, but writing to the catalog once gives the best backtest performance.

DataFusion streams Nautilus Parquet data from disk at high throughput, at least an order of magnitude faster than decoding DBN per run.

:::note Performance benchmarks are under development. :::

Loading DBN data

The DatabentoDataLoader class loads DBN files and converts records to Nautilus objects. Two primary uses:

• Pass data to BacktestEngine.add_data for backtesting.
• Write data to ParquetDataCatalog for streaming with a BacktestNode.

DBN data to a BacktestEngine

Load DBN data and pass to a BacktestEngine. The engine requires an instrument. This example uses TestInstrumentProvider (an instrument parsed from a DBN file also works). The data covers one month of TSLA trades on Nasdaq:

# Add instrument
TSLA_NASDAQ = TestInstrumentProvider.equity(symbol="TSLA")
engine.add_instrument(TSLA_NASDAQ)

# Decode data to Cython objects
loader = DatabentoDataLoader()
trades = loader.from_dbn_file(
    path=TEST_DATA_DIR / "databento" / "temp" / "tsla-xnas-20240107-20240206.trades.dbn.zst",
    instrument_id=TSLA_NASDAQ.id,
)

# Add data
engine.add_data(trades)

DBN data to a ParquetDataCatalog

Load DBN data and write to a ParquetDataCatalog. Set as_legacy_cython=False to decode as PyO3 objects.

Loading instruments

Important: Load instrument definitions from DEFINITION schema files before loading market data into a catalog. The catalog requires instruments before it can store market data. Market data files do not contain instrument definitions.

# Initialize the catalog interface
# (will use the `NAUTILUS_PATH` env var as the path)
catalog = ParquetDataCatalog.from_env()

loader = DatabentoDataLoader()

# Step 1: Load instrument definitions FIRST
# You must obtain DEFINITION schema files from Databento for your instruments
instruments = loader.from_dbn_file(
    path=TEST_DATA_DIR / "databento" / "temp" / "tsla-xnas-definition.dbn.zst",
    as_legacy_cython=False,  # Use PyO3 for optimal performance
)

# Write instruments to catalog
catalog.write_data(instruments)

# Step 2: Now load and write market data
instrument_id = InstrumentId.from_str("TSLA.XNAS")

# Decode trades to pyo3 objects
trades = loader.from_dbn_file(
    path=TEST_DATA_DIR / "databento" / "temp" / "tsla-xnas-20240107-20240206.trades.dbn.zst",
    instrument_id=instrument_id,
    as_legacy_cython=False,  # This is an optimization for writing to the catalog
)

# Write market data
catalog.write_data(trades)

Loading multiple data types for backtesting

Always load instruments before market data:

from nautilus_trader.adapters.databento.loaders import DatabentoDataLoader
from nautilus_trader.model.identifiers import InstrumentId
from nautilus_trader.persistence.catalog import ParquetDataCatalog

catalog = ParquetDataCatalog.from_env()
loader = DatabentoDataLoader()

# Step 1: Load instrument definitions from DEFINITION files
instruments = loader.from_dbn_file(
    path="equity-definitions.dbn.zst",
    as_legacy_cython=False,
)
catalog.write_data(instruments)

# Step 2: Load market data (MBO, trades, quotes, etc.)
instrument_id = InstrumentId.from_str("AAPL.XNAS")

# Load MBO order book deltas
deltas = loader.from_dbn_file(
    path="aapl-mbo.dbn.zst",
    instrument_id=instrument_id,  # Optional but improves performance
    as_legacy_cython=False,
)
catalog.write_data(deltas)

# Load trades
trades = loader.from_dbn_file(
    path="aapl-trades.dbn.zst",
    instrument_id=instrument_id,
    as_legacy_cython=False,
)
catalog.write_data(trades)

# Verify instruments are in the catalog
print(catalog.instruments())  # Should show your loaded instruments

:::tip Call catalog.instruments() to verify. An empty list means you need to load DEFINITION files first. :::

:::info Download DEFINITION schema files through the Databento API or CLI for your symbols and date ranges. See the Databento documentation for details. :::

:::info See also the Data concepts guide. :::

Historical loader options

Parameters for from_dbn_file:

• instrument_id: Speeds up decoding by skipping symbology lookup.
• price_precision: Overrides the default price precision.
• include_trades: For MBP-1/CMBP-1 schemas, True emits both QuoteTick and TradeTick when trade data is present.
• as_legacy_cython: Set to False for IMBALANCE/STATISTICS schemas (required) or for better catalog write performance.

:::warning IMBALANCE and STATISTICS schemas require as_legacy_cython=False (PyO3-only types). True raises a ValueError. :::

Loading consolidated data

Consolidated schemas aggregate data across multiple venues:

# Load consolidated MBP-1 quotes
loader = DatabentoDataLoader()
cmbp_quotes = loader.from_dbn_file(
    path="consolidated.cmbp-1.dbn.zst",
    instrument_id=InstrumentId.from_str("AAPL.XNAS"),
    include_trades=True,  # Get both quotes and trades if available
    as_legacy_cython=True,
)

# Load consolidated BBO quotes
cbbo_quotes = loader.from_dbn_file(
    path="consolidated.cbbo-1s.dbn.zst",
    instrument_id=InstrumentId.from_str("AAPL.XNAS"),
    as_legacy_cython=False,  # Use PyO3 for better performance
)

# Load TCBBO (trade-sampled consolidated BBO) - provides both quotes and trades
# Note: include_trades=True loads quotes, include_trades=False loads trades
tcbbo_quotes = loader.from_dbn_file(
    path="consolidated.tcbbo.dbn.zst",
    instrument_id=InstrumentId.from_str("AAPL.XNAS"),
    include_trades=True,  # Loads quotes
    as_legacy_cython=True,
)

tcbbo_trades = loader.from_dbn_file(
    path="consolidated.tcbbo.dbn.zst",
    instrument_id=InstrumentId.from_str("AAPL.XNAS"),
    include_trades=False,  # Loads trades
    as_legacy_cython=True,
)

:::tip Avoid subscribing to both TBBO/TCBBO and separate trade feeds for the same instrument. These schemas already include trades. Duplicating wastes cost and creates duplicate data. :::

Real-time client architecture

The DatabentoDataClient wraps the other Databento adapter classes. Each dataset uses two DatabentoLiveClient instances:

• One for MBO (order book deltas) real-time feeds
• One for all other real-time feeds

:::warning All MBO subscriptions for a dataset must be made at node startup to replay from session start. Subscriptions after start are logged as errors and ignored.

This limitation does not apply to other schemas. :::

A single DatabentoHistoricalClient serves both DatabentoInstrumentProvider and DatabentoDataClient for historical requests.

Configuration

Add a DATABENTO section to your TradingNode client configuration:

from nautilus_trader.adapters.databento import DATABENTO
from nautilus_trader.live.node import TradingNode

config = TradingNodeConfig(
    ...,  # Omitted
    data_clients={
        DATABENTO: {
            "api_key": None,  # 'DATABENTO_API_KEY' env var
            "http_gateway": None,  # Override for the default HTTP historical gateway
            "live_gateway": None,  # Override for the default raw TCP real-time gateway
            "instrument_provider": InstrumentProviderConfig(load_all=True),
            "instrument_ids": None,  # Nautilus instrument IDs to load on start
            "parent_symbols": None,  # Databento parent symbols to load on start
        },
    },
    ..., # Omitted
)

Create the TradingNode and register the factory:

from nautilus_trader.adapters.databento.factories import DatabentoLiveDataClientFactory
from nautilus_trader.live.node import TradingNode

# Instantiate the live trading node with a configuration
node = TradingNode(config=config)

# Register the client factory with the node
node.add_data_client_factory(DATABENTO, DatabentoLiveDataClientFactory)

# Finally build the node
node.build()

Configuration parameters

:::tip Use environment variables for credentials. :::

Connection stability

The live client reconnects automatically on:

• Network interruptions: Temporary connectivity issues.
• Gateway restarts: Databento Sunday maintenance (see Maintenance Schedule).
• Market closures: Sessions ending during off-hours.

Reconnection strategy

Backoff strategy depends on the timeout configuration:

With timeout (default 10 minutes):

• Exponential backoff capped at 60 seconds.
• Pattern: 1s, 2s, 4s, 8s, 16s, 32s, 60s, 60s... (with jitter).
• Reconnects quickly within the timeout window.

Without timeout (reconnect_timeout_mins=None):

• Exponential backoff capped at 10 minutes.
• Pattern: 1s, 2s, 4s, 8s, 16s, 32s, 64s, 128s, 256s, 512s, 600s, 600s... (with jitter).
• Suited for unattended systems through overnight closures and scheduled maintenance.

All reconnections include:

• Jitter: Random delay (up to 1 second) to prevent simultaneous reconnection storms.
• Automatic resubscription: Restores all active subscriptions after reconnecting.
• Cycle reset: Each successful session (>60s) resets the timeout clock.

Timeout configuration

The reconnect_timeout_mins parameter controls how long the client attempts reconnection:

Default (10 minutes): Suitable for most use cases.

• Handles transient network issues.
• Survives scheduled gateway restarts.
• Stops retrying overnight when markets close.
• Requires manual intervention for longer outages.

:::warning Setting reconnect_timeout_mins=None retries indefinitely. Use only for unattended systems that must survive overnight market closures. This can mask persistent configuration or authentication issues. :::

Scheduled maintenance

Databento restarts live gateways every Sunday (all clients disconnect):

The default 10-minute timeout covers typical restarts. For unattended systems, use reconnect_timeout_mins=None or a longer value. See the Databento Maintenance Schedule for details.

Contributing

:::info To contribute, see the contributing guide. :::