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Connection

Connect to the Kalshi WebSocket endpoint:
No authentication is required for WebSocket connections.

Subscribing to markets

Once connected, send a JSON message to subscribe using klsi_id:

Unsubscribing

Message types

Price messages

Real-time price updates for subscribed markets:

Orderbook messages

Real-time orderbook snapshots for subscribed markets:

Trade messages

Real-time trade executions for subscribed markets:

Full example

Important notes

  • No authentication required for WebSocket connections
  • Use klsi_id (Kalshi market identifier) to subscribe
  • Messages are only sent for markets you have explicitly subscribed to
  • Multiple markets can be subscribed in a single message
  • Trades must be explicitly requested (not included in the default subscription)