What is Kotlin Multiplatform?

The problem KMP solves

Building the same app for Android and iOS traditionally means writing everything twice — the networking, the data models, the business rules — once in Kotlin and again in Swift. That’s double the work and double the bugs, and the two versions drift apart over time.

Kotlin Multiplatform (KMP) lets you write that shared logic once in Kotlin and reuse it on Android, iOS, desktop, web and the server. Each platform still gets a fully native app — only the “brain” is shared.

Share the logic, keep native UIs

This is the key idea. With KMP you typically share the non-UI parts and let each platform build its own native interface (Jetpack Compose on Android, SwiftUI on iOS). Optionally, with Compose Multiplatform, you can share the UI too — but that’s a choice, not a requirement.

What you typically share

• Networking and API calls.
• Data models and JSON serialization.
• Database, caching and offline logic.
• Business rules and validation.
• Presentation logic (ViewModels/state).

KMP vs Flutter / React Native

Flutter and React Native usually share the whole app including the UI, using their own rendering. KMP takes a different philosophy: share what makes sense, stay native where it matters. Your iOS app can use SwiftUI and feel 100% native while still reusing all your Kotlin logic. This appeals to teams who value the native look and the latest OS features.

Is it production-ready?

Yes — KMP is stable and used in production by major companies (including parts of apps at Netflix, McDonald’s, Philips and many others). It’s backed by JetBrains and Google.

What you should already know

KMP builds directly on Kotlin, so you should be comfortable with the Kotlin language first (classes, coroutines, sealed classes). The Kotlin course in this Academy is the ideal prerequisite.

Common misconceptions

• “KMP shares the UI” — by default it shares logic; UI sharing (Compose Multiplatform) is optional.
• “It’s all or nothing” — you can start by sharing just one module (like networking).
• “iOS developers must learn Kotlin deeply” — they consume the shared code like any library.

Summary: KMP lets you write business logic once in Kotlin and reuse it across Android, iOS and more, while each platform keeps a native UI. Share the brain, keep native faces — and adopt it gradually, one module at a time.