> ## Documentation Index
> Fetch the complete documentation index at: https://pmxt-sync-hosted-docs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# 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.
**Available on:** Polymarket, Opinion, Limitless. Other venues raise `NotSupported` in hosted mode — for those, run a [local PMXT service](/guides/self-hosted).
**Before your first call:** deposit USDC on Polygon at [pmxt.dev/dashboard/wallet](https://pmxt.dev/dashboard/wallet) (one-time setup). For the programmatic flow, see [escrow lifecycle](/guides/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.
## OpenAPI
````yaml /api-reference/openapi-hosted-trading.json post /v0/orders/cancel/build
openapi: 3.0.0
info:
title: PMXT Hosted Router API
description: Hosted-only endpoints for cross-venue search, matching, arbitrage, and SQL.
version: 49fbcd4
servers:
- url: https://trade.pmxt.dev
description: Hosted trading (v0)
security:
- bearerAuth: []
tags:
- name: Trading (Hosted)
description: >-
Hosted trading endpoints. Build / submit / cancel orders via
`trade.pmxt.dev/v0/*`. Hosted-mode is the default when `pmxt_api_key` is
set.
- name: Orders & Positions (Hosted)
description: >-
Hosted account reads. Open orders, fills, balances, and positions via
`trade.pmxt.dev/v0/*`. Requires `pmxt_api_key` + `wallet_address`.
- name: MatchedMarkets
description: Cross-venue matched market and event clusters.
- name: SQL
description: Direct read-only SQL access to the catalog (Enterprise).
paths:
/v0/orders/cancel/build:
post:
tags:
- Trading
summary: Cancel Order
description: >-
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.
operationId: cancelOrderHosted
requestBody:
required: true
content:
application/json:
schema:
$ref: '#/components/schemas/CancelBuildHostedRequest'
responses:
'200':
description: Cancel build response.
content:
application/json:
schema:
$ref: '#/components/schemas/CancelBuildHostedResponse'
'401':
description: Invalid or missing PMXT API key.
content:
application/json:
schema:
$ref: '#/components/schemas/HostedErrorResponse'
'404':
description: Order not found.
content:
application/json:
schema:
$ref: '#/components/schemas/HostedErrorResponse'
'422':
description: Invalid order ID.
content:
application/json:
schema:
$ref: '#/components/schemas/HostedErrorResponse'
x-codeSamples:
- lang: python
label: Polymarket
source: >
# 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)
- lang: javascript
label: Polymarket
source: >
// Current hosted venues are funded once on Polygon — see
/guides/escrow-lifecycle.
// Hosted writes need: pmxtApiKey + walletAddress + privateKey
(signs EIP-712 locally).
import { Polymarket } from "pmxtjs";
const client = new Polymarket({
pmxtApiKey: "YOUR_PMXT_API_KEY",
walletAddress: "0xYourWallet", // EVM address — its Polygon USDC funds the escrow
privateKey: "0x...", // any EVM key controlling that address
});
const cancelled = await client.cancelOrder("order_abc123");
console.log(cancelled.id, cancelled.status);
- lang: python
label: Opinion
source: >
# 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.Opinion(
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)
- lang: javascript
label: Opinion
source: >
// Current hosted venues are funded once on Polygon — see
/guides/escrow-lifecycle.
// Hosted writes need: pmxtApiKey + walletAddress + privateKey
(signs EIP-712 locally).
import { Opinion } from "pmxtjs";
const client = new Opinion({
pmxtApiKey: "YOUR_PMXT_API_KEY",
walletAddress: "0xYourWallet", // EVM address — its Polygon USDC funds the escrow
privateKey: "0x...", // any EVM key controlling that address
});
const cancelled = await client.cancelOrder("order_abc123");
console.log(cancelled.id, cancelled.status);
components:
schemas:
CancelBuildHostedRequest:
type: object
required:
- order_id
- user_address
properties:
order_id:
type: string
description: Unified order id, as returned by `fetchOpenOrdersHosted`.
user_address:
type: string
description: >-
EVM wallet address that owns the resting order and will sign the
cancel typed data.
CancelBuildHostedResponse:
type: object
required:
- cancel_id
- typed_data
- deadline
properties:
cancel_id:
type: string
description: >-
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:
type: object
description: >-
EIP-712 typed-data payload to sign locally with the wallet key
matching `user_address`. Return the signature when submitting the
cancel.
pull_typed_data:
type: object
nullable: true
description: >-
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.
deadline:
type: integer
description: >-
Unix epoch (s) after which the cancel build expires. Submit the
signed cancel before this time or call `cancelOrderHosted` again.
HostedErrorResponse:
type: object
description: >-
Error envelope returned by `trade.pmxt.dev/v0/*` endpoints. Mirrors the
`ErrorDetail` shape used inside `BaseResponse.error` from the sidecar
spec.
required:
- error
properties:
error:
type: object
description: Structured error envelope. Always present on non-2xx responses.
properties:
message:
type: string
description: Human-readable explanation safe to surface to end users.
code:
type: string
description: >-
Stable hosted-mode error code. Use this (not `message`) for
branching in client code.
enum:
- HOSTED_TRADING_ERROR
- INSUFFICIENT_ESCROW_BALANCE
- ORDER_SIZE_TOO_SMALL
- INVALID_API_KEY
- OUTCOME_NOT_FOUND
- CATALOG_UNAVAILABLE
- BUILT_ORDER_EXPIRED
- INVALID_SIGNATURE
- NO_LIQUIDITY
- MISSING_WALLET_ADDRESS
- ORDER_NOT_FOUND
- INVALID_ORDER
retryable:
type: boolean
description: >-
`true` when the same request may succeed if retried (e.g.
transient catalog outage); `false` when the caller must change
inputs first.
exchange:
type: string
nullable: true
description: >-
Source venue that produced the error (e.g. `polymarket`,
`opinion`, `limitless`), when the failure originated upstream of
PMXT. `null` for PMXT-side errors.
detail:
type: object
additionalProperties: {}
nullable: true
description: >-
Free-form structured diagnostics (e.g. required minimum size,
escrow balance available). Shape varies per `code`.
securitySchemes:
bearerAuth:
type: http
scheme: bearer
description: >-
Required when calling the hosted API directly (curl, requests, fetch).
SDK users pass credentials via constructor params instead.
````