Damian Rubio developed Appstack attribution integration for the RevenueCat/purchases-android repository, enabling developers to leverage attribution data for improved targeting and real-time offerings synchronization. He designed and implemented a new public API in Kotlin, allowing ingestion of Appstack attribution parameters and mapping them to subscriber attributes, including a reserved identifier. The integration was wired through core Android SDK flows, updating components such as PurchasesOrchestrator and SubscriberAttributesManager. Damian ensured robust unit testing, covering attribute mapping, edge cases, and coroutine behavior. His work focused on API integration, Android development, and unit testing, delivering a well-architected, maintainable feature that reduces integration friction.