Abstract
While MVP and CLEAN Architecture are popular Android patterns, they often introduce boilerplate or lack reactivity. This article introduces the Reactive Data Layer Architecture (RDLA), an offline-first, push-based data layer pattern designed for modern Android apps using Jetpack Compose and Room. Using a heart rate tracking example, we demonstrate how RDLA provides robust local-remote synchronization, clean separation of concerns without Use Case overhead, and simplified unit testing via the TestExtensions pattern.