6. WebSocket

The push-only real-time channel for Market Data and Trading events.

What is FastConnect's WebSocket used for?

Receiving real-time market data (channel DATA: trades, bid/ask, foreign room...) and trading events (channel TRADING: order fills, asset changes) over a single WebSocket connection — no need for separate connections per data type like before. This is a receive-only (push-only) channel; to send orders over WebSocket, see "7. WebSocket API".

Why does my WebSocket connection keep disconnecting?

Common causes:

  • Not replying with pong when receiving ping from the server (the server sends a heartbeat every 30 seconds).
  • Unstable network or a firewall blocking the WebSocket connection.

Your client needs to implement its own reconnect logic and re-subscribe to topics after reconnecting.

Can I subscribe to multiple data types on the same connection?

Yes — send multiple topics in a single SUBSCRIBE message (for example, several symbols, or both channel DATA and TRADING), as long as your API Key has the corresponding scope for each topic type.

5. FastConnect Market Data

Data latency, historical data, and the unified model for equity/derivative instruments.

7. WebSocket API

Sending orders purely over WebSocket — status, permissions, and how it differs from the regular WebSocket.