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

# Heartbeat

> Server heartbeat sent when no subscription traffic is detected

<div className="api-banner">
  <span className="api-protocol ws">WSS</span>
  <span className="api-detail">ws.kraken.com</span>
  <span className="api-tag">heartbeat</span>
</div>

Server heartbeat sent if no subscription traffic within approximately 1 second. Heartbeats are only sent if there is an active connection with at least one subscription.

## Payload

<ResponseField name="event" type="string">
  Value: `heartbeat`
</ResponseField>

<Panel>
  <CodeGroup>
    ```json Heartbeat theme={null}
    {
      "event": "heartbeat"
    }
    ```
  </CodeGroup>
</Panel>