> ## 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.

# Index price

> Subscribe to index price updates for a single symbol via WebSocket using the SPOT symbol format.

Push interval: 1s

For index price, use SPOT symbol such as `SPOT_ETH_USDC` instead of `PERP_ETH_USDC`

```json theme={null}
{
  "id": "clientID7",
  "topic": "SPOT_ETH_USDC@indexprice",
  "event": "subscribe"
}
```

**Parameters**

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

<RequestExample>
  ```json Response theme={null}
  {
    "id": "clientID7",
    "event": "subscribe",
    "success": true,
    "ts": 1682241351985
  }
  ```
</RequestExample>

<ResponseExample>
  ```json Subscribed Message theme={null}
  {
    "topic": "SPOT_ETH_USDC@indexprice",
    "ts": 1682241354000,
    "data": {
      "symbol": "SPOT_ETH_USDC",
      "price": 1873.36
    }
  }
  ```
</ResponseExample>