KMP: Shared Logic Without Shared UI

When we started our Kotlin Multiplatform project, the temptation was to share everything — including UI. We resisted that urge, and it turned out to be the right call.

The approach

Our shared module handles three things: networking (Ktor), local caching (SQLDelight), and domain logic. Everything above that layer is platform-native.

On Android, we use Jetpack Compose. On iOS, SwiftUI. The shared Kotlin code compiles to a framework that iOS consumes directly.

Why not share UI?

Compose Multiplatform is impressive, but our iOS users expect iOS-native behavior. Swipe-back navigation, platform haptics, accessibility patterns — these are hard to replicate in a cross-platform UI layer.

Results

• 60% code sharing by line count
• Native feel on both platforms
• One team maintaining shared logic
• Platform teams focus on UI polish

The key insight: share the boring parts (networking, caching, business rules) and let each platform shine where it matters most.