Download Deferred Deep Linking for Android – Play Install Referrer FREE Unity.
Deferred Deep Linking for Android is a direct implementation of Google Play Install Referrer API, it enables your unity applications or games to return the install referrer information in order to track installs, give users rewards, etc.
The plugin doesn’t require any configuration from your part, and the integration is simple and quick. Featurewise it also has a built-in cache for the referrer information (that you can turn off if needed) and direct integration with Universal Deep Linking plugin.
Finally, it contains a built-in test tool, so that you can test the plugin integration directly from the Unity Editor.