Modify Order

Modify existing orders by changing their price and/or quantity. This is essentially a cancel-and-replace operation that maintains the order's position in the queue while updating its parameters.

Endpoint

POST https://papi.synthetix.io/v1/trade

Request

Request Format

{
  "params": {
    "action": "modifyOrder",
    "subAccountId": "1867542890123456789",
    "orderId": "12345",
    "price": "45000.50",
    "quantity": "2.50"
  },
  "nonce": 1703123456789,
  "signature": {
    "v": 27,
    "r": "0x5a3c2b1d4e5f6789abcdef0123456789abcdef0123456789abcdef0123456789",
    "s": "0x1a2b3c4d5e6f7890abcdef0123456789abcdef0123456789abcdef0123456789"
  },
  "expiresAfter": 1703123456789
}

Request Parameters

Response

Success Response

{
  "status": "ok",
  "response": {
    "orderId": "12345",
    "status": "modified",
    "price": "45000.50",
    "quantity": "2.50"
  },
  "request_id": "req-123456789",
  "timestamp": "2025-01-01T00:00:00Z"
}

Error Response

{
  "status": "error",
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Order not found or does not belong to this subaccount",
    "details": null
  },
  "request_id": "req-123456789",
  "timestamp": "2025-01-01T00:00:00Z"
}

Response Fields

Code Examples

Modify Order Price Only

{
  "params": {
    "action": "modifyOrder",
    "orderId": "12345",
    "price": "49000.00"
  },
  "nonce": 1703123456789,
  "signature": {
    "v": 27,
    "r": "0x5a3c2b1d4e5f6789abcdef0123456789abcdef0123456789abcdef0123456789",
    "s": "0x1a2b3c4d5e6f7890abcdef0123456789abcdef0123456789abcdef0123456789"
  },
  "subAccountId": "1",
}

Modify Order Quantity Only

{
  "params": {
    "action": "modifyOrder",
    "orderId": "12346",
    "quantity": "0.50"
  },
  "nonce": 1703123466789,
  "signature": {
    "v": 27,
    "r": "0x5a3c2b1d4e5f6789abcdef0123456789abcdef0123456789abcdef0123456789",
    "s": "0x1a2b3c4d5e6f7890abcdef0123456789abcdef0123456789abcdef0123456789"
  },
  "subAccountId": 1
}

Modify Both Price and Quantity

{
  "params": {
    "action": "modifyOrder",
    "orderId": "12347",
    "price": "95.50",
    "quantity": "5.00"
  },
  "nonce": 1703123476789,
  "signature": {
    "v": 27,
    "r": "0x5a3c2b1d4e5f6789abcdef0123456789abcdef0123456789abcdef0123456789",
    "s": "0x1a2b3c4d5e6f7890abcdef0123456789abcdef0123456789abcdef0123456789"
  },
  "subAccountId": "1",
  "expiresAfter": 1703123506789
}

Important Behavior

• Queue Position: The operation preserves the order's position in the queue when possible
• Atomic Operation: The modify operation is atomic - either the entire modification succeeds or fails
• Partial Modification: If only one field (price or quantity) is provided, the other field retains its current value
• Precision: All monetary values use string representation to avoid floating-point precision issues

Validation Rules

Request Validation

1. Action Type: Must be exactly "modifyOrder"
2. Order ID: Must be a valid positive integer string
3. Modification Fields: At least one of price, quantity, or triggerPrice must be provided
4. Price Format: If provided, must be a valid decimal string
5. Quantity Format: If provided, must be a valid decimal string
6. Trigger Price Format: If provided, must be a valid decimal string
7. Order Existence: The order must exist and belong to the specified subaccount
8. Signature Verification: EIP-712 signature must be valid for the request parameters

Business Logic Validation

• Order must be in an open/active state
• Cannot modify orders that are already filled or cancelled
• Price/quantity changes must comply with market rules
• Account must have sufficient margin for the modification

Authentication & Authorization

• Request must include valid EIP-712 signature using the ModifyOrder typed data structure
• nonce must be a timestamp in milliseconds and must be increasing per address
• Each nonce can only be used once (replay protection)
• expiresAfter timestamp must be in the future (if provided)

{
  "name": "Synthetix",
  "version": "1",
  "chainId": 1,
  "verifyingContract": "0x0000000000000000000000000000000000000000"
}

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

Error Handling

Common error scenarios: