Heartbeat (cancel-on-disconnect)

POST/v1/px/heartbeatscancel scope

Market Maker APIE6 decimal strings throughoutA | B

Send periodic heartbeats. If one is not received in time, the server cancels all of your open orders.

Send X-PX-Key: pxk_…. This endpoint requires the cancel scope — an insufficient scope returns 403, not 401, and this line does not use Bearer sessions. To request a key and see the limits, visit the onboarding page.

Behaviour

Send an empty heartbeatId on the first request; afterwards send the heartbeatId from the previous response.
Every response returns a new heartbeatId; the previous one becomes invalid immediately.
Send one every 5s. If no valid heartbeat arrives within 10s, all open orders are cancelled with cancelReason = HEARTBEAT_TIMEOUT.
A mismatched heartbeatId returns 409 HEARTBEAT_ID_MISMATCH with the currently valid id. Two processes sharing one key will trigger this error.

Request

curl -X POST "{BASE_URL}/v1/px/heartbeats" \
  -H "X-PX-Key: $PX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "heartbeatId": "" }                      // first call
{ "heartbeatId": "hb_01K5H2M3N7Q8R9S0" }   // every 5s after that'

Response

The request was accepted

200 { "heartbeatId": "hb_01K5H2M3N7Q8R9S1", "timeoutMs": 10000 }
409 { "code": "HEARTBEAT_ID_MISMATCH", "heartbeatId": "hb_01K5H2M3N7Q8R9S1", "requestId": "…" }