WebSocket Market Streams Overview

Live prices, candles and statistics. Market streams are public — no API key, no signature, no login. Account events are on a separate, authenticated connection: User Data Streams Overview.

Endpoints

On the raw endpoint, payloads arrive exactly as documented below.

On the combined endpoint, every payload is wrapped:

{"stream":"XAUUSD@tick","data":{"e":"tick","E":1789012345678,"s":"XAUUSD","b":"2331.15","a":"2331.42","l":"2331.15","v":8,"bd":1,"ad":-1,"T":1789012345678}}

Streams in the streams= query parameter are separated by /. URL-encode the value if a symbol name contains a character that needs it.

Subscribe protocol

Send JSON text frames.

SUBSCRIBE

{"method":"SUBSCRIBE","params":["XAUUSD@tick","BTCUSD@kline_1m"],"id":1}

{"result":null,"id":1}

UNSUBSCRIBE

{"method":"UNSUBSCRIBE","params":["XAUUSD@tick"],"id":2}

{"result":null,"id":2}

LIST_SUBSCRIPTIONS

{"method":"LIST_SUBSCRIPTIONS","id":3}

{"result":["BTCUSD@kline_1m"],"id":3}

Request fields

Error frames

{"code":-1121,"msg":"Invalid symbol.","id":1}

{"code":-1120,"msg":"Invalid interval.","id":4}

{"code":-1101,"msg":"Too many parameters sent for this endpoint.","id":5}

An error frame never closes the connection. UNSUBSCRIBE of a stream you are not subscribed to is a no-op and answers success.

A SUBSCRIBE with several params is all-or-nothing: if one name is invalid the whole frame is rejected and nothing is subscribed. Subscribe in small batches so one bad symbol does not cost you the rest.

Codes are the same ones documented in Error Codes.

Connection limits

• Reply to every WebSocket ping frame with a pong. Most client libraries do this automatically; verify yours does. A missed pong window costs you the connection.
• You may send unsolicited pong frames as a heartbeat; they are ignored and do not count toward the message rate.
• A connection is closed at 24 hours regardless of activity. Reconnect before then. Overlap the connections — open the new one, subscribe, then drop the old one — so you do not miss ticks.
• Exceeding 10 inbound messages per second closes the connection immediately. Batch stream names into one SUBSCRIBE rather than sending one frame per stream.
• Exceeding 200 streams returns -1101 and subscribes nothing.
• A connection beyond the per-IP limit — or beyond the service's overall capacity — is refused before the WebSocket upgrade with HTTP 503 and -1008. Put your streams on fewer connections (up to 200 each) rather than opening one per symbol.
• A plain HTTP request (no WebSocket upgrade) to a stream URL is answered HTTP 400 with -1020.
• An inbound message larger than 64 KB closes the connection.
• On the pre-subscribed and combined URLs, an invalid stream name in the URL is answered with one error frame (as above, "id":null) and the connection is then closed — nothing is subscribed.

The server closes a connection with these WebSocket close codes:

There are no rate-limit weight headers on WebSocket. Market streams do not consume REST request weight, which is exactly why you should use them instead of polling.

Reconnect guidance

Market streams carry no state and are not replayed. On reconnect:

1. Re-subscribe to everything you had. LIST_SUBSCRIPTIONS on the new connection is the way to verify, not to discover.
2. Refresh anything you were accumulating from the stream: candles from GET /v1/klines, and any last-price cache from GET /v1/ticker/price.
3. Assume you missed ticks during the gap. Never derive position state from the tick stream — read it from GET /v1/positions.

Reconnect with backoff and jitter. A fleet of bots reconnecting in lockstep after a restart is self-inflicted load.