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

# Open interest

### Topic: openinterest@`{symbol}`

Push interval: push every 1 second if open interest change and 10 seconds force update even if no change.\
Subscribe to open interest.

<RequestExample>
  ```bash Subscribed messages theme={null}
  {
    "id": .....
    "cmd": "SUBSCRIBE",
    "params": ["openinterest@PERP_BTC_USDT"]
  }
  ```
</RequestExample>

<ResponseExample>
  ```bash theme={null}
  {
      "topic": "openinterest@PERP_BTC_USDT",
      "ts": 1618820361552,
      "data": {
          "s": "PERP_BTC_USDT",  // symbol
          "oi": "936.37",        // open interest
          "ts": 1618820200000    // time of last update
      }
  }
  ```
</ResponseExample>