Room is Android's recommended persistence library—an abstraction layer over SQLite that uses Kotlin/Java annotations to define database schema, queries, and migrations. It generates type-safe DAO (Data Access Object) classes at compile time, catching SQL errors before runtime. Room integrates seamlessly with Jetpack's LiveData, Flow, and Coroutines for reactive data binding and asynchronous queries. The library ships with Android Architecture Components and is the standard for offline-first Android apps, local caching, and on-device relational data. Every modern Android project uses Room for persistent storage.