Workshop: Migrate to Room KMP — Shared Database Layer Without the Abstraction Tax

What We Are Building In this workshop, I will walk you through migrating a production app from separate persistence stacks — Room on Android, GRDB on iOS — to a single shared Room KMP database layer. By the end, you will have unified entity definitions, one set of migrations that runs on both platforms, and platform-specific SQLite tuning using expect/actual . Let me show you a pattern I use in every project that adopts KMP for real. Prerequisites Kotlin 2.0+ with KMP configured for Android and iOS targets Room 2.7.0-alpha+ (the first version with official KMP support) An existing Room database on Android (or willingness to create one) Xcode 15+ for iOS builds Step 1 — Move Your Schema to commonMain Start here, not with migrations. Move your @Entity and @Dao definitions into commonMain . Keep the RoomDatabase.Builder platform-specific using expect/actual . // commonMain @Entity data class Project ( @PrimaryKey ( autoGenerate = true ) val id : Long = 0 , val name : String , val archived