Cross-platform development has historically required painful compromises between code sharing and native quality. Kotlin Multiplatform takes a fundamentally different approach: sharing business logic, data layers, and networking code across platforms while keeping the UI completely native. In 2026, KMP has matured into a production-ready solution adopted by major companies including Netflix, Cash App, and Philips.

How KMP Works

Kotlin Multiplatform compiles Kotlin code to each target platform's native format: JVM bytecode for Android, native binaries for iOS, JavaScript for web, and JVM or native for desktop. The shared code lives in a common module, with platform-specific implementations using expect/actual declarations. This means your networking layer, data models, business logic, and domain rules are written once and tested once, while the UI layer uses each platform's native framework. The result is true code sharing without sacrificing native user experience.

Advantages Over Alternatives

Compared to React Native or Flutter, KMP preserves platform-native UI, resulting in better performance and more natural user interactions. Compared to writing everything twice, KMP eliminates the duplication of business logic that leads to divergent behavior and maintenance burden. The incremental adoption model means teams can start by sharing a single module and expand sharing over time without rewriting existing code. Kotlin's interoperability with Java and Swift means KMP modules integrate naturally into existing Android and iOS projects.

Compose Multiplatform

JetBrains Compose Multiplatform extends Jetpack Compose to iOS, desktop, and web, enabling UI code sharing alongside business logic sharing. While still maturing for iOS production use, Compose Multiplatform offers a path toward sharing more of the application stack. For teams willing to accept the trade-offs, it enables sharing up to 90 percent of code across all platforms. For most teams, sharing business logic with native UI remains the pragmatic sweet spot.

Architecture and Best Practices

Successful KMP projects follow clear architectural patterns. Clean architecture with shared domain and data layers and platform-specific presentation layers provides the best balance of sharing and flexibility. Dependency injection frameworks like Koin or Dagger support multiplatform projects. SQLDelight provides type-safe database access across platforms. Ktor offers a multiplatform HTTP client. These libraries form a mature ecosystem that supports production development.

Getting Started

The fastest path to KMP adoption is identifying a new feature that targets both Android and iOS, sharing the business logic layer for that feature, and validating the approach with a production release. This incremental approach reduces risk, builds team expertise, and demonstrates value before committing to a full platform migration. JetBrains provides templates and documentation that accelerate project setup, and the community has produced extensive resources for common patterns and challenges.