Native UI without duplicate logic
SwiftUI and Compose stay exactly as your platform teams built them. What disappears is the second implementation of every business rule, API client and edge case.
Technologies
Kotlin Multiplatform
Business logic written once in Kotlin, UI kept fully native: SwiftUI on iOS, Jetpack Compose on Android. No rewrite required to start.
What it is
Kotlin Multiplatform shares the code where most bugs live: networking, data models, validation, sync, business rules. Each platform keeps a fully native interface in SwiftUI and Jetpack Compose, so nothing about how the app looks or feels is compromised. Typical products end up sharing 40 to 70 percent of their code, and every shared line is written, tested and fixed once.
It wins where React Native and Flutter do not fit: you already have two native apps and teams, the platform look and feel is non-negotiable, or your domain logic is complex enough that duplicating it is your real cost. Adoption is incremental. The first shared module goes into your existing apps in weeks, no rewrite, no big-bang migration, and you can stop at any point with working software.
The honest trade-offs: you still build two user interfaces, so KMP saves less per feature than a shared-UI framework; iOS build integration adds tooling work; and the library ecosystem is younger than React Native's or Flutter's. Since JetBrains declared it stable in late 2023 and Google made it the recommended path for sharing logic, teams at Netflix, Forbes and McDonald's run it in production. We will tell you plainly whether your codebase is a fit.
Why it works
Adopt without a rewrite
KMP compiles to an XCFramework your iOS app consumes like any other dependency. The first module lands in your shipping apps within weeks, and each further module is a separate decision.
One source of truth for the hard parts
Pricing rules, offline sync, validation: written once, unit-tested once, fixed once. The class of bug where iOS and Android disagree simply goes away.
A bet with institutional backing
Kotlin Multiplatform is stable, maintained by JetBrains and recommended by Google for sharing business logic. It builds on the language your Android team already writes.
Technologies
How we introduce it
01
Audit the duplication
We map both codebases and price the overlap: which logic exists twice, how often it changes, where the platforms disagree today. That is the business case, in numbers.
02
Ship a real module first
The first shared module is production code in your live apps, an API client or the sync engine, not a demo. It proves the build pipeline, the iOS interop and the team workflow at once.
03
Expand along the seams
Module by module we move domain logic into the shared core, in the order the audit ranked. Each step ships independently, and a pause always leaves a working whole.
04
Make both teams owners
iOS engineers learn to consume, then contribute to, the shared code; Android engineers learn to design APIs that feel right in Swift. We leave when the pipeline and the habits are yours.
What you get
Shared Kotlin modules running inside your production iOS and Android apps
Architecture blueprint: what is shared, what stays native, and why
Build and publishing pipeline: XCFramework, Swift Package or CocoaPods, Maven
Test suite for the shared core, running on both platforms in CI
Sequenced migration roadmap for the remaining duplicated logic
Enablement for both platform teams: docs and hands-on sessions
Common questions
How much code can we realistically share?
Typically 40 to 70 percent, depending on how much of your app is domain logic versus interface. That is less than React Native or Flutter promise, but it is the half where the expensive bugs live, and it comes without giving up native UI. The audit gives you the number for your codebase before you commit.
Do our iOS developers have to write Kotlin?
No. The shared code arrives as a standard framework with Swift-friendly APIs, and consuming it looks like using any third-party library. In practice most iOS teams start contributing to the shared module within a few months, because the alternative is waiting; that is a choice, not a requirement.
Is Kotlin Multiplatform production-ready?
Yes. JetBrains declared it stable in November 2023, Google recommends it for sharing logic between Android and iOS, and Netflix, Forbes, McDonald's and Cash App run it in production. The younger corner is Compose Multiplatform for shared UI; we assess that separately and recommend it only where it is ready.
KMP, React Native or Flutter?
Greenfield app, small team, conventional UI: React Native or Flutter usually wins on total cost. Two existing native apps, strong platform teams, complex domain logic: KMP wins, because it removes the duplication without throwing away what you built. You get the comparison for your case in writing.
Stop building every feature twice
A free 30-minute call with a senior mobile architect. Bring your two codebases; you leave with a first estimate of what is worth sharing.
Talk to a mobile architect