Cancel Order

Start a cancel on an existing open order. Returns the cancel payload for the wallet to sign — you then submit the signature to POST /v0/orders/cancel.

The SDK’s cancelOrder() chains both steps. Call this endpoint directly only if you need to show the cancel to a user before signing.

POST /v0/orders/cancel/build

Python

Polymarket

# Current hosted venues are funded once on Polygon — see /guides/escrow-lifecycle.
# Hosted writes need: pmxt_api_key + wallet_address + private_key (signs EIP-712 locally).
import pmxt

client = pmxt.Polymarket(
    pmxt_api_key="YOUR_PMXT_API_KEY",
    wallet_address="0xYourWallet",    # EVM address — its Polygon USDC funds the escrow
    private_key="0x...",    # any EVM key controlling that address
)
cancelled = client.cancel_order("order_abc123")
print(cancelled.id, cancelled.status)

200

{
  "cancel_id": "<string>",
  "typed_data": {},
  "deadline": 123,
  "pull_typed_data": {}
}

{
  "error": {
    "message": "<string>",
    "retryable": true,
    "exchange": "<string>",
    "detail": {}
  }
}

{
  "error": {
    "message": "<string>",
    "retryable": true,
    "exchange": "<string>",
    "detail": {}
  }
}

{
  "error": {
    "message": "<string>",
    "retryable": true,
    "exchange": "<string>",
    "detail": {}
  }
}

Available on: Polymarket, Opinion, Limitless. Other venues raise NotSupported in hosted mode — for those, run a local PMXT service.

Before your first call: deposit USDC on Polygon at pmxt.dev/dashboard/wallet (one-time setup). For the programmatic flow, see escrow lifecycle.

Use any EVM private key. Your USDC sits in a non-custodial PreFundedEscrow on Polygon — for Polymarket, Opinion, and Limitless. PMXT cannot move funds without your EIP-712 signature.

Authorizations

Authorization · string · header · required

Required when calling the hosted API directly (curl, requests, fetch). SDK users pass credentials via constructor params instead.

Body

application/json

order_id · string · required

Unified order id, as returned by fetchOpenOrdersHosted.

user_address · string · required

EVM wallet address that owns the resting order and will sign the cancel typed data.

Response

200

application/json

Cancel build response.

cancel_id · string · required

Opaque server-side key for this cancel build. Pass it to POST /v0/orders/cancel with the EIP-712 signature(s) before deadline.

typed_data · object · required

EIP-712 typed-data payload to sign locally with the wallet key matching user_address. Return the signature when submitting the cancel.

deadline · integer · required

Unix epoch (s) after which the cancel build expires. Submit the signed cancel before this time or call cancelOrderHosted again.

pull_typed_data · object | null

Optional secondary EIP-712 payload for venues that require a pull-authorization cancel (Polymarket neg-risk markets). Sign with the same wallet and return as pull_signature. null when not required.