cancel (gRPC) | Hyperliquid API Docs

Cancel existing orders on Hyperliquid by order ID. Used for order management and risk control.

Cancel one or more existing orders by their order ID (oid). This action removes orders from the order book before they can be filled.

Sample Data

JSON

{
  "signature": {
    "r": "0xb7233b2b2b0cf0eb161f86319be9a86c197f860dbcbe4d4f189e5fa757137c89",
    "s": "0x65e5d0ffd58b0bf7ed168a8d1a9b6f8df6050c7acf24db588fb62f9390e9a2c3",
    "v": 27
  },
  "action": {
    "type": "cancel",
    "cancels": [
      {
        "a": 0,
        "o": 291379970288
      }
    ]
  },
  "nonce": 1768146913376
}

View this transaction on Hypurrscan

Field Reference

Action Fields

Field	Type	Description
`type`	string	Always `"cancel"`
`cancels`	array	Array of cancel requests

Cancel Object Fields

Field	Type	Description
`a`	number	Asset index of the order to cancel
`o`	number	Order ID (oid) to cancel

Optional Fields

Field	Type	Description
`vaultAddress`	string	Vault address if cancelling vault orders

Use Cases

Order Management Systems

Track cancellation activity to understand order lifecycle and fill rates:

Python

def process_cancel_action(action):
    for cancel in action.get('cancels', []):
        asset = cancel['a']
        order_id = cancel['o']

        print(f"Order cancelled: asset={asset}, oid={order_id}")

Risk Management

Monitor cancellation patterns to detect:

High cancellation rates (potential spoofing)
Emergency position exits
Market maker quote updates

Market Making Analytics

Analyze the ratio of order placements to cancellations to understand market maker behavior and quote refresh rates.

order - Submit new orders
cancelByCloid - Cancel by client order ID
scheduleCancel - Schedule future cancellation

cancel - Cancel Orders by ID