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

# Event

> Vobiz generates call events when the state of a call changes - your application receives them as HTTP requests so it can update state and trigger logic.

Vobiz generates events when the state of a call changes to let the application know about the progress of the call.

Vobiz will send one of these values under the Event parameter:

## Event values

| Value              | Description                                                                                                                |
| ------------------ | -------------------------------------------------------------------------------------------------------------------------- |
| `StartApp`         | The call was answered and is currently in progress. You can terminate it with the Hangup API.                              |
| `Transfer`         | The call was transferred with the Transfer API. Vobiz sends this event to the target URL associated with the transfer XML. |
| `Redirect`         | The call was redirected with the Redirect XML element.                                                                     |
| `MachineDetection` | Machine detection was requested for an outbound API call. Vobiz sends this event to the configured machine-detection URL.  |

### Example response

```json theme={null}
true
```