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Kotlin Multiplatform Development
Build Android and iOS apps from a shared codebase, without giving up native performance or platform-specific behaviour. Kotlin Multiplatform lets you write business logic once and deploy it to both platforms, reducing cost and keeping your codebase consistent as your product grows.
What Is Kotlin Multiplatform?
Kotlin Multiplatform (KMP) is a technology from JetBrains that lets you write shared Kotlin code that compiles to Android, iOS, web, and desktop targets. Unlike React Native or Flutter, KMP does not replace the native UI layer; it shares the logic underneath it.
This means your ViewModels, data layer, business logic, Firebase integration, and offline sync all live in shared Kotlin code. The UI layer uses Compose on Android and can use Compose Multiplatform or SwiftUI on iOS, giving you native platform behaviour where it matters most.
What Gets Shared, What Stays Native
Shared (Kotlin Multiplatform)
- ViewModels and UI state management
- UseCases and business logic
- Repository and data coordination layer
- Firebase / Firestore integration
- Offline-first sync logic
- Data models and domain types
- Error handling infrastructure
- Analytics and event tracking
Platform-Specific (Native)
- Compose UI (Android) or SwiftUI (iOS)
- Deep links and system navigation
- Platform permissions (camera, location)
- Push notification handling
- Platform-specific file access
- In-app purchase platform APIs
Why Choose Kotlin Multiplatform
Faster Iteration
Fix a bug in shared code and it's fixed on both platforms. Add a feature to the data layer once and both apps benefit immediately.
Lower Maintenance Cost
Half the platform-specific logic means half the places a bug can hide. Shared code is tested once and trusted everywhere.
Native Performance
KMP compiles to native, with no bridge or virtual machine overhead. Your app behaves like a native Android or iOS app because it is one.
Architectural Consistency
One architecture, one set of patterns, one place to enforce standards. Both platforms stay in sync as the product evolves.
Growing Ecosystem
KMP adoption is accelerating. Google and JetBrains are investing heavily, with multiplatform support for Jetpack libraries landing regularly.
Gradual Adoption
You don't need to rewrite. KMP can be introduced incrementally: start with shared data models, then business logic, then more as confidence grows.
AMPM: A Kotlin Multiplatform Learning Platform
AMPM is a South African exam prep app built entirely on Kotlin Multiplatform and Compose Multiplatform. The shared codebase covers the full architecture: ViewModels, UseCases, Repositories, DataSources, and Firebase integration, all written once in Kotlin and targeting Android from day one, with iOS as a natural next step using the same shared core.
When KMP Makes Sense
Building for Android and iOS
Share the logic layer and write native UI on each platform. You get genuinely native apps without duplicating your business rules.
Existing Android app, adding iOS
Extract shared logic from your Android app into a KMP module. iOS gets a head start, with the data layer and business logic already written and tested.
Team with Kotlin experience
If your team already writes Kotlin for Android, KMP is a natural extension. The language is identical; only the targets change.
App with significant business logic
The more complex your domain logic, the more you benefit from writing it once. Rule-heavy apps, complex data pipelines, and offline-sync scenarios are ideal KMP candidates.
KMP Libraries on Maven Central
The infrastructure patterns we use in production are published as open-source libraries. Both are available on Maven Central under Apache 2.0.
arrow-errors
Type-safe error handling for KMP. Turns raw exceptions into actionable objects with severity, presentation mode, and navigation directives, plus ready-to-use Compose Material 3 components.
GitHub →arrow-http
Client-agnostic HTTP abstraction for KMP. Your repositories depend on the core interface; the Ktor implementation handles auth refresh, retry policies, and platform-specific engines.
GitHub →Considering Kotlin Multiplatform?
Whether you're starting a new cross-platform app or migrating an existing Android app to KMP, let's talk through what makes sense for your project.
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