POST/heartbeats

Send heartbeat

Sends a heartbeat signal to maintain active session status. If heartbeats are not sent regularly, all open orders for the user will be automatically canceled. This is useful for automated trading systems that need to ensure orders are canceled if the system becomes unresponsive.

Base URL: https://clob.polymarket.com
Auth: L2 API credentials (key, secret, passphrase)POLY_API_KEY, POLY_ADDRESS, POLY_SIGNATURE, POLY_PASSPHRASE, POLY_TIMESTAMP
Rate limit: 9,000 req / 10s (900 per second)
Limit applies to: CLOB API general

Example

curl -X POST "https://clob.polymarket.com/heartbeats" \
  -H "POLY_API_KEY: $POLY_API_KEY" \
  -H "POLY_ADDRESS: $POLY_ADDRESS" \
  -H "POLY_SIGNATURE: $POLY_SIGNATURE" \
  -H "POLY_PASSPHRASE: $POLY_PASSPHRASE" \
  -H "POLY_TIMESTAMP: $POLY_TIMESTAMP"

L2 requests are signed with HMAC-SHA256 using your API secret, and the timestamp is part of the signature, so keep the machine's clock accurate. A missing credential or a stale signature both come back as Unauthorized/Invalid api key. The Python SDK signs for you.

Response fields

Field	Type	Description
status	string	Status of the heartbeat acknowledgment

Responses

Status	Meaning
200	Heartbeat acknowledged
401	Unauthorized - Invalid API key or authentication failed
500	Internal server error

Polymarket's API serves current state only, so it cannot show what a market's book looked like after it resolved. PolyTest records Up/Down markets while they run and keeps the snapshots. Try it free, or read the full rate limit reference.

From Polymarket's published OpenAPI spec and rate-limit tables, synced 2026-10-04.