Stream live market data

Use Data Socket when your application needs continuous market updates rather than repeated REST requests.

Plan check Data Socket symbol limits are per user, across all connections: Standard supports 100 symbols and Prime supports 5,000. See Plans & rate limits.

Step-by-step workflow

1. 1

   Authenticate the socket connection

   Prepare the verified socket authentication value using the active FYERS API session. Do not place credentials directly in logs or client-visible output.

2. 2

   Open a connection

   Create the Data Socket connection and register handlers for connection, message, error and close events.

3. 3

   Subscribe to symbols

   Subscribe only to the symbols and data type required by the workflow. Keep the subscription count within the applicable Standard or Prime limit.

4. 4

   Process incoming updates

   Validate each message type before reading its fields. Update the application state using the latest event rather than assuming every message has the same structure.

5. 5

   Change or remove subscriptions

   Unsubscribe from symbols that are no longer required and update the local subscription list so the application and socket stay aligned.

6. 6

   Reconnect safely after interruption

   Reconnect with controlled backoff, restore only the required subscriptions and avoid opening multiple active connections for the same workflow.

7. 7

   Verify the result

   Check the relevant API response and account or market-data state to confirm that the workflow completed successfully. If the result is partial or unsuccessful, review the returned status and message before deciding whether to retry or take another action.

Common issues

HTTP/1.1 401 Unauthorized
{"s":"error","code":-8,"message":"Could not authenticate the user"}

HTTP/1.1 400 Bad Request
{"s":"error","code":-50,"message":"Please provide valid order parameters"}

HTTP/1.1 429 Too Many Requests
Retry-After: 1
{"s":"error","message":"Rate limit exceeded"}

Error: socket hang up
ECONNRESET

Related API reference

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