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Endpoint

Each connection is scoped to exactly one subaccount. To watch orders across multiple subaccounts, open one connection per subaccount. The server pushes a snapshot of currently-open orders on connect, then a frame every time one of that subaccount’s orders changes user-visible status.

Query parameters

Authentication

Browser clients

Browsers cannot set request headers on a WebSocket upgrade, so a first-party web client passes its Supabase JWT in the subprotocol list rather than the URL. Offer two values — the bare marker and the token-bearing one — and the server selects the marker:
A credential in a query string is written verbatim into every intermediary’s request log, which is why ?access_token= is no longer accepted. Programmatic clients are unaffected: the signed-handshake params are safe to log, because sig is bound to the path, query and timestamp and is single-use. Browsers can’t set custom headers on the WebSocket handshake, so the signed-request flow moves to query params. The signature covers WS\nPATH\nSORTED_QUERY (excluding key_id/ts/sig)\nTIMESTAMP.
The official SDKs sign the handshake for you. The raw recipe below is for integrations without an SDK.
Signed handshake
The authenticated user must own subaccount_id — otherwise the connection is closed with code 4401. A missing or malformed subaccount_id is closed with 4400.

Protocol

All frames are JSON. Server frames are bytes (orjson-serialized UTF-8). Client frames are accepted but ignored — there is no subscribe/unsubscribe action; the subaccount is fixed at handshake time.

Server → client

  • connected is sent immediately after the handshake completes.
  • snapshot follows once, listing orders currently in pending, resting, or partially_filled for this subaccount. The client always sees state, then deltas — never the other way around.
  • order frames deliver every user-visible status transition. The internal processing status is never forwarded.
  • reconnect is sent during graceful pod shutdown. Reconnect with a small jitter.

Statuses

Iceberg child tranches arrive as ordinary order frames — clients can’t tell them apart from user-placed simple orders.

Order payload

Default fields (always sent):
When connected with ?extra_information=true, every row additionally carries:
average_price is null until the first fill. traded_qty and fees_paid default to 0. complex_order_ids lists attached take-profit / stop-loss conditional-order ids by side; both buckets are empty when nothing is attached. order_type and time_in_force are the canonical enum names (LIMIT, MARKET, GTC, IOC, FOK, …).

Keepalive

Liveness is handled at the WebSocket protocol layer (RFC 6455 PING/PONG control frames). Standard clients (Python websockets, browser WebSocket) reply to server PINGs automatically — no application-level heartbeat is needed.

Minimal client

Using the SDK (handles signing automatically):
Order fields arrive at the top level of each frame and are readable as attributes (msg.id, msg.status, …). The subaccount is fixed at handshake time — there is no subscribe / unsubscribe on this stream; open one connection per subaccount. Or signing the handshake manually:

Errors

Recoverable problems arrive as an error frame followed by a close. code is stable and safe to branch on; message is human-readable.

Close codes