> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vobiz.ai/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:

## List of Event values

Value

Description

`StartApp`

The call was answered and is currently in progress. Calls with this status can be explicitly terminated using the Hangup API.

`Transfer`

The call was transferred using the Transfer API. This event is sent to the target URL of the XML you return from the transfer URL.

`Redirect`

The call was redirected using the Redirect XML element.

`MachineDetection`

Vobiz generates this event when the machine\_detection parameter is used in the Outbound Call API request. The event is sent to the machine\_detection URL.

### Example Response

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