> For the complete documentation index, see [llms.txt](https://docs.ep.mburger.cloud/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ep.mburger.cloud/flutter-docs/audience/custom-id.md).

# Custom Id

You can set a custom id in order to track/target users with id coming from different platforms.

To set a custom id:

```dart
MBAudience.setCustomId('CUSTOM_ID');
```

To remove it:

```dart
MBAudience.removeCustomId();
```

To retrieve the current saved id:

```dart
String customId = await MBAudience.getCustomId();
```