# App — Message Acknowledge

The **Acknowledge** message acknowledges the receipt of a distinct message by the LiSA Player.

This is particularly important for messages that require confirmation to ensure they are reliably received and not lost.

This message is sent by the LiSA Player to the host app / environment.

### Properties

Along with all standard [Message properties](https://docs.hello-lisa.com/developers/guides/player-communication/message-api-reference/..#properties), a **Message Acknowledge** message includes the following additional properties:

<table><thead><tr><th width="239" valign="top">Name</th><th width="162" valign="top">Type</th><th valign="top">Description</th></tr></thead><tbody><tr><td valign="top"><code>messageId</code></td><td valign="top"><pre><code>String
</code></pre><p>Required.</p></td><td valign="top">The <code>messageId</code> property is used to specify the distinct identifier of the message being acknowledged. </td></tr><tr><td valign="top"><code>messageType</code></td><td valign="top"><pre><code>Literal
</code></pre><p>Required.</p></td><td valign="top"><code>lsc:app:message:acknowledge</code></td></tr></tbody></table>

***

### Type Definition

```typescript
interface AppMessageAcknowledgeMessage extends Omit<
  Message,
  'messageId' | 'messageType' | 'sender'
> {
  messageId: string;
  messageType: 'lsc:app:message:acknowledge';
  sender: 'LiSA';
}
```

***

### Examples

```json
{
  "clockDriftInMs": 0,
  "messageId": "a84eccd0-8834-4e70-b011-de0472c40681",
  "messageType": "lsc:app:message:acknowledge",
  "sender": "LiSA"
}
```