Kotlin Multiplatform
What is Kotlin Multiplatform, exactly?
Kotlin Multiplatform (KMP, formerly KMM for the mobile-specific variant) lets a single Kotlin codebase produce platform-native binaries for iOS, Android, JVM server, JavaScript, and native desktop targets. Unlike Flutter or React Native, KMP does not unify the UI layer — each platform keeps its own native UI framework (SwiftUI or UIKit on iOS, Jetpack Compose on Android). Only the shared layers — business logic, networking, persistence, domain models — are written once.
KMP has been a JetBrains project since 2017 and reached stable in November 2023. Compose Multiplatform — the optional UI layer that does unify rendering — went stable on iOS in May 2024.
When does DevMind reach for KMP?
We choose KMP when at least two of these are true:
- The team already runs Kotlin server-side or on Android, so there’s no new language to onboard.
- More than half of the codebase is non-UI logic that’s currently duplicated across iOS and Android.
- The iOS team is comfortable consuming a Kotlin-generated Swift framework as a dependency in their build chain.
- The product needs feature parity on both platforms simultaneously, not staggered releases.
We avoid KMP for tiny single-screen apps where the cross-platform overhead exceeds the saved duplication, and for projects where the iOS team can’t tolerate a non-Swift binary in their build.
How does KMP compare to alternatives?
Versus Flutter: KMP keeps native UI; Flutter unifies it. Pick KMP when each platform should feel native to its users; pick Flutter when brand-consistent UI across platforms matters more than platform conventions.
Versus React Native: KMP shares less of the stack (logic only, not UI), so the iOS feel-and-touch is preserved at the cost of more per-platform UI work. React Native is faster to ship a “good enough” shared UI; KMP wins on long-term iOS UX quality.
Versus fully native (separate Swift + Kotlin): KMP eliminates duplicating every domain model and API call. The trade-off is a learning curve on the iOS side, where Swift developers consume the generated framework and have to think about Kotlin idioms occasionally bleeding through.
DevMind’s perspective
KMP is our default cross-platform choice when the customer cares about a native iOS feel. We’ve shipped KMP in production for mobile and automotive companion apps and treat it as a long-term-friendly choice — JetBrains is committed, the toolchain stabilises with every release, and the path back to fully native exists if you ever need it.
Related DevMind services
Mobile App Development and Automotive Software — both are areas where we’ve shipped Kotlin Multiplatform in production.