Kotlin Multiplatform (KMP): The Native Cross-Platform Solution

Philosophy: Logic vs UI

KMP assumes UI is culture. iOS users want iOS UI. Android users want Android UI. But the API calls and Data models? They are the same. Share them.

Kotlin compiles to JVM (Android) and LLVM Native (iOS). You write 'Common' code, which becomes a framework in Xcode and a library in Android Studio.

Use Ktor for networking and SQLDelight/Room for databases. These libraries have platform-specific drivers but a common Kotlin API.

Swift calls Kotlin code easily. New improvements (SKIE) make modern Swift features (Async/Await, Enums) map perfectly to Kotlin.

JetBrains now allows sharing UI too via Compose. It renders on iOS like Flutter (drawing on canvas). Optional, but powerful.

No bridge performance cost. No "uncanny valley" UI. You can adopt it incrementally in existing native apps.

Start with a small, isolated module (e.g., Analytics or a specific feature's data layer). Don't rewrite the whole app at once.