Binance Onchain-Pay Open API Authentication

Signing Process

All Onchain-Pay Open API requests use RSA SHA256 signature with a PEM private key.

Step 1: Build the Signing Payload

payload = JSON_BODY + TIMESTAMP

JSON_BODY: The raw JSON request body string (compact, no trailing newline). If no body is needed, use empty string.
TIMESTAMP: Current Unix timestamp in milliseconds (e.g., 1709654400000)

Example:

{"fiatCurrency":"USD","cryptoCurrency":"BTC","totalAmount":100,"amountType":1}1709654400000

Step 2: Sign with RSA SHA256

bash

signature=$(echo -n "$payload" \
  | openssl dgst -sha256 -sign "$PRIVATE_KEY_PATH" \
  | openssl enc -base64 -A)

Uses the RSA private key in PEM format
SHA256 digest
Base64 encoded (single line, no wrapping)

Step 3: Send Request with Headers

All requests are POST with these headers:

Header	Value
`X-Tesla-ClientId`	Your client ID (e.g., `your-client-id`)
`X-Tesla-SignAccessToken`	Your API key
`X-Tesla-Signature`	The RSA signature from Step 2
`X-Tesla-Timestamp`	The timestamp used in signing
`Content-Type`	`application/json`
`x-trace-id`	(Optional) Trace ID for debugging

Complete Example

bash

# Generate timestamp in milliseconds (cross-platform compatible)
timestamp=$(($(date +%s) * 1000))
api_params='{"fiatCurrency":"USD","cryptoCurrency":"BTC","totalAmount":100,"amountType":1}'
payload="${api_params}${timestamp}"

signature=$(echo -n "$payload" \
  | openssl dgst -sha256 -sign "test.pem" \
  | openssl enc -base64 -A)

curl --location --request POST "https://api.commonservice.io/papi/v1/ramp/connect/buy/payment-method-list" \
  --header "X-Tesla-ClientId: your-client-id" \
  --header "X-Tesla-SignAccessToken: your-api-key" \
  --header "X-Tesla-Signature: $signature" \
  --header "X-Tesla-Timestamp: $timestamp" \
  --header "Content-Type: application/json" \
  --data-raw "$api_params"

Important: Cross-platform Timestamp Generation

Correct (works on macOS, Linux, BSD):

bash

timestamp=$(($(date +%s) * 1000))

Incorrect (do not use):

bash

# ❌ Doesn't work on macOS - outputs literal 'N'
timestamp=$(date +%s%3N)

# ❌ Just appends '000', not true milliseconds
timestamp=$(date +%s000)

On macOS, date doesn't support %N (nanoseconds), which causes date +%s%3N to output something like 1773744478N. This breaks JSON parsing with error:

Unexpected character ('N' (code 78)): was expecting comma to separate Object entries

Security Notes

Never expose the PEM private key content
Never display the full API key; show first 5 + last 4 characters only (e.g., 2zefb...06h)
The PEM file path should be absolute or relative to the working directory