Cancel Orders (WebSocket)

Cancel one or more existing orders through the WebSocket connection for fastest order management.

Action Result Notifications

This method executes cancellations immediately. Cancellation events are automatically sent via SubAccount Updates Subscription if subscribed.

Endpoint

ws.send() wss://api.synthetix.io/v1/ws/trade

Request

Request Format

{
  "id": "cancel-1",
  "method": "post",
  "params": {
    "action": "cancelOrders",
    "subAccountId": "1867542890123456789",
    "orderIds": ["1948058938469519360", "1948058938469519361"],
    "nonce": 1704067200000,
    "expiresAfter": 1704067300,
    "signature": {
      "v": 28,
      "r": "0x1234567890ABCDEF1234567890ABCDEF1234567890ABCDEF1234567890ABCDEF",
      "s": "0xABCDEF1234567890ABCDEF1234567890ABCDEF1234567890ABCDEF1234567890"
    }
  }
}

Parameters

Request Parameters

Parameter	Type	Required	Description
`id`	string	Yes	Client-generated unique request identifier
`method`	string	Yes	Must be `"post"`
`params`	object	Yes	Contains all parameters for the request

Params Object

Parameter	Type	Required	Description
`action`	string	Yes	Must be `"cancelOrders"`
`subAccountId`	string	Yes	Subaccount ID to cancel orders from
`orderIds`	array	Yes	Array of order IDs to cancel (strings)
`nonce`	integer	Yes	Unique incrementing number (typically Unix timestamp in ms)
`expiresAfter`	integer	No	Optional expiration Unix timestamp in seconds (0 = no expiration)
`signature`	object	Yes	EIP-712 signature with v, r, s components

EIP-712 Type Definition

const CancelOrdersTypes = {
  CancelOrders: [
    { name: "subAccountId", type: "uint256" },
    { name: "orderIds", type: "uint256[]" },
    { name: "nonce", type: "uint256" },
    { name: "expiresAfter", type: "uint256" }
  ]
}

Note: orderIds is uint256[] in EIP-712, but sent as string[] in the JSON request body.

Response Format

Success Response

{
  "id": "cancel-1",
  "status": 200,
  "result": {
    "status": "success",
    "response": {
      "statuses": [
        {
          "orderId": "1948058938469519360",
          "message": "Canceled"
        },
        {
          "orderId": "1948058938469519361",
          "message": "Canceled"
        }
      ]
    }
  }
}

Partial Success Response

If some orders fail to cancel, individual order statuses will contain error messages:

{
  "id": "cancel-1",
  "status": 200,
  "result": {
    "status": "success",
    "response": {
      "statuses": [
        {
          "orderId": "1948058938469519360",
          "message": "Canceled"
        },
        {
          "orderId": "1948058938469519361",
          "message": "Order not found"
        }
      ]
    }
  }
}

Error Response

{
  "id": "cancel-1",
  "status": 400,
  "result": null,
  "error": {
    "code": 400,
    "message": "Invalid request parameters"
  }
}

Implementation Example

// Cancel single order
const subAccountId = "1867542890123456789";
const nonce = Date.now();
const expiresAfter = Math.floor(Date.now() / 1000) + 30; // 30 seconds from now
 
// Create EIP-712 signature (see EIP-712 Signing section below)
const signature = await signCancelOrders({
  subAccountId,
  orderIds: ["1948058938469519360"],
  nonce,
  expiresAfter
});
 
const cancelRequest = {
  id: "cancel-1",
  method: "post",
  params: {
    action: "cancelOrders",
    subAccountId,
    orderIds: ["1948058938469519360"],
    nonce,
    expiresAfter,
    signature
  }
};
 
ws.send(JSON.stringify(cancelRequest));
 
// Cancel multiple orders
const cancelMultiple = {
  id: "cancel-2",
  method: "post",
  params: {
    action: "cancelOrders",
    subAccountId,
    orderIds: ["1948058938469519360", "1948058938469519361", "1948058938469519362"],
    nonce: Date.now(),
    expiresAfter: Math.floor(Date.now() / 1000) + 30,
    signature: await signCancelOrders({
      subAccountId,
      orderIds: ["1948058938469519360", "1948058938469519361", "1948058938469519362"],
      nonce: Date.now(),
      expiresAfter: Math.floor(Date.now() / 1000) + 30
    })
  }
};
 
ws.send(JSON.stringify(cancelMultiple));
 
// Handle response
ws.onmessage = (event) => {
  const response = JSON.parse(event.data);
 
  if (response.id === "cancel-1") {
    if (response.result?.status === "success") {
      response.result.response.statuses.forEach(status => {
        console.log(`Order ${status.orderId}: ${status.message}`);
      });
    } else if (response.error) {
      console.error(`Error: ${response.error.message}`);
    }
  }
};

Implementation Notes

Cancellation requests must include at least one order ID
Order IDs must belong to the authenticated subaccount
Authentication timestamps must be monotonically increasing per subaccount
EIP-712 domain separator must use "Synthetix" for WebSocket endpoints

Cancellation Behavior

Only OPEN and PARTIALLY_FILLED orders can be cancelled
Filled portions of partially filled orders remain executed
Cancellation is immediate upon validation
Freed margin becomes available instantly

Signing

All trading methods are signed using EIP-712. Each successful trading request will contain:

A piece of structured data that includes the sender address
A signature of the hash of that structured data, signed by the sender

For detailed information on EIP-712 signing, see EIP-712 Signing.

Nonce Management

The nonce system prevents replay attacks and ensures order uniqueness:

Use current timestamp in milliseconds as nonce
Each nonce must be greater than the previous one
Recommended: Use Date.now() or equivalent
If nonce conflicts occur, increment by 1 and retry

:::note SubAccountAction Exception SubAccountAction endpoints (getPositions, getOpenOrders, getOrdersHistory, getTrades, getFundingPayments, getSubAccount, getDelegatedSigners, getBalanceUpdates) do not require a nonce. Only the signature and optional expiresAfter parameters are needed. :::

Error	Description
Invalid signature	EIP-712 signature validation failed
Invalid market symbol	Market symbol not recognized
Nonce already used	Nonce must be greater than previous value
Rate limit exceeded	Too many requests in time window
Request expired	`expiresAfter` timestamp has passed

Next Steps

Modify Order - Order modification via WebSocket
Cancel All Orders - Emergency cancellation
REST Alternative - REST API comparison