Orchestration API

POST /cancel-order

Builds a cancellation transaction for an existing limit order.

This endpoint builds a cancellation transaction for an existing limit order. The returned payload must be signed and submitted to the blockchain by the caller to complete the cancellation.

TypeScript Types: Generate types for this API with a single command. See Type Generation.

API Reference: For detailed schema definitions and interactive testing, see the API Reference.

Request

Endpoint

POST /cancel-order

Headers

Content-Type: application/json
x-api-key: YOUR_API_KEY

Body Parameters

Field	Type	Required	Description
`orderId`	`string`	Yes	The ID of the limit order to cancel
`chain`	`Chain`	Yes	The chain where the order was placed

Example Request

import type { components } from "./m0-swap"; // From type generation

type CancelOrderResponse = components["schemas"]["CancelOrderResponse"];

const response = await fetch("https://orchestration-api.m0.xyz/cancel-order", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    "x-api-key": YOUR_API_KEY,
  },
  body: JSON.stringify({
    orderId: "0xabc123...", // The limit order ID
    chain: "Ethereum",
  }),
});

if (!response.ok) {
  const error = await response.text();
  throw new Error(`Cancel order failed: ${error}`);
}

const result: CancelOrderResponse = await response.json();

Response

Success Response (200)

Returns a CancelOrderResponse object containing the transaction payload to submit on-chain to complete the cancellation.

import type { components } from "./m0-swap";

type CancelOrderResponse = components["schemas"]["CancelOrderResponse"];

Response Fields

Field	Type	Description
`orderId`	`string`	The ID of the order being cancelled
`chain`	`Chain`	The chain where the cancellation transaction must be sent
`payload`	`TransactionPayload`	The signed transaction data to submit to cancel the order

The payload field follows the same TransactionPayload structure as quote payloads -- either an EvmPayload or SvmPayload depending on the chain. See the Quote docs for payload execution examples.

Error Responses

Status	Description
`404`	Order not found -- the `orderId` does not exist on the specified `chain`
`409`	Order cannot be cancelled -- it may already be filled, expired, or cancelled
`500`	Internal server error

Example Response

{
  "orderId": "0xabc123...",
  "chain": "Ethereum",
  "payload": {
    "type": "evm",
    "chain": "Ethereum",
    "chainId": 1,
    "to": "0x1234567890abcdef...",
    "data": "0xabcdef...",
    "value": "0"
  }
}

Executing the Cancellation

Once you have the response, submit the payload to the blockchain to complete the cancellation:

import { createWalletClient, http } from "viem";
import { mainnet } from "viem/chains";
import type { components } from "./m0-swap";

type EvmPayload = components["schemas"]["EvmPayload"];

async function executeCancelOrder(payload: EvmPayload, account: `0x${string}`) {
  const client = createWalletClient({
    chain: mainnet,
    transport: http(),
    account,
  });

  const hash = await client.sendTransaction({
    to: payload.to as `0x${string}`,
    data: payload.data as `0x${string}`,
    value: BigInt(payload.value),
  });

  return hash;
}

Notes

Only the original order creator can cancel a limit order
A 409 response means the order is in a terminal state (filled, expired, or already cancelled) and no action is needed
The cancellation is not final until the returned transaction payload is submitted and confirmed on-chain

API Reference

Overview of M0's Orchestration API (REST) and Protocol API (GraphQL).

GET /order-status/{orderId}

Returns the status and details for a single order ID.