> ## Documentation Index
> Fetch the complete documentation index at: https://orderly.network/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Mark price

> Subscribe to mark price updates for a single symbol via WebSocket, pushed every second.

Push interval: 1s

```json theme={null}
{
  "id": "clientID8",
  "topic": "PERP_ETH_USDC@markprice",
  "event": "subscribe"
}
```

**Parameters**

| Name  | Type   | Required | Description               |
| ----- | ------ | -------- | ------------------------- |
| id    | string | Y        | id generate by client     |
| event | string | Y        | `subscribe`/`unsubscribe` |
| topic | string | N        | `{symbol}@markprice`      |

<RequestExample>
  ```json Response theme={null}
  {
    "id": "clientID8",
    "event": "subscribe",
    "success": true,
    "ts": 1682241795883
  }
  ```
</RequestExample>

<ResponseExample>
  ```json Subscribed Message theme={null}
  {
    "topic": "PERP_ETH_USDC@markprice",
    "ts": 1682241796000,
    "data": {
      "symbol": "PERP_ETH_USDC",
      "price": 2300.0
    }
  }
  ```
</ResponseExample>