When to use WebSocket
Use streams for monitoring, alerts, and pre-trade checks; use REST for history and ad-hoc queries. Do not replace stream with aggressive polling.
Subscribe payload
After connecting to /api/v1/market/stream, send action=subscribe with market and symbols. Symbol count is plan-capped.
Message types
Expect subscribed ack, then type=tick frames. Errors arrive as type=error with a code such as WS_CONN_LIMIT.
Billing and limits
Handshake counts toward quota/RPM; ticks are not metered per message. Connection and symbol caps apply by plan.
Related reading
See /docs/api/stream and the WebSocket vs REST glossary entry.