# Status webhooks

Follow a call from ringing to its final status.

Set `webhook_url` when you [place a call](/docs/call-api). Vonyx sends a `POST` to it each time the call's status changes:

1. `ringing`
2. `in-progress`
3. The final status: `completed`, `busy`, `no-answer` and others

The final update includes the call's duration and who ended it. Every update carries `CallUUID`, the `call_id` from the original response.

<Callout title="Retry safely">
  If placing a call returns `504`, the call may still have been placed. Check your webhook for its `CallUUID` before retrying, so the person isn't called twice.
</Callout>