Kotlin Multiplatform

Kotlin Multiplatform development services for apps that share code without losing native feel.

I build and ship Kotlin Multiplatform apps — sharing business logic, networking, and data across Android, iOS, and desktop while keeping each platform's UI native. If you're evaluating KMP for a real product rather than a proof of concept, this is the page for that conversation.

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01What Kotlin Multiplatform development covers

Kotlin Multiplatform lets you write the parts of an app that don't need to look different per platform — networking, data models, persistence, business rules, validation — once, in Kotlin, and reuse that module on Android, iOS, and desktop. The UI stays separate: Jetpack Compose on Android, SwiftUI (or Compose Multiplatform) on iOS, and whatever fits the desktop target.

That split matters. The apps that regret going multiplatform are usually the ones that tried to share UI code before the underlying logic was solid, or shared things — like screen-specific state — that should have stayed platform-native. My default is to share the boring, high-value layer first: API clients, local database access with SQLDelight, caching, and domain logic. UI comes later, and only where it earns its keep.

02When shared code pays off — and when it does not

The honest pitch for KMP is narrower than the marketing around it: it pays off when your Android and iOS apps do genuinely similar things — same data model, same business rules, same backend — and you want to fix a bug or ship a feature once instead of twice. It pays off less when the platforms diverge heavily in behavior, or when you only ever plan to ship one of them.

A useful signal: if you already have a native Android app and are scoping an iOS version, the shared module is usually where the estimate drops the most — the logic that took weeks to get right on Android does not need to be re-derived on iOS, just re-wired to a Swift UI layer.

03How a KMP engagement runs

The process is the same shape as any build here — scope, architect, build, ship, maintain — with the architecture step doing more work up front for multiplatform projects, because the shared/platform-specific boundary has to be right before the codebase grows around it.

  • Scope: map what genuinely needs to be shared versus what stays platform-native, before writing code.
  • Architect: design the shared Kotlin module — networking, persistence (SQLDelight/Room), domain logic — with clean interfaces to each platform UI.
  • Build: implement the shared module plus native UI, Compose on Android and SwiftUI or Compose Multiplatform on iOS.
  • Ship: release builds, CI, and store submission for both platforms from one pipeline where practical.
  • Maintain: keep the shared module current as Kotlin, Compose, and platform SDKs move forward.

04Migrating an existing native app to KMP

Most KMP work I do is not a greenfield rewrite — it is an existing native Android app that needs an iOS counterpart, or two separate native codebases that have drifted and need a shared source of truth. The practical path is incremental: extract the networking and data layer into a Kotlin module first, prove it works on both platforms, then move business logic module by module. Rewriting the UI layer in one shot is rarely worth the risk; native UI code usually stays as it is.

05Compose Multiplatform, when you need shared UI too

Kotlin Multiplatform on its own only shares logic — the UI stays native per platform. If you also want the interface itself shared across desktop and mobile, that is a further step covered on the Compose Multiplatform development page linked below, and it is a different set of tradeoffs worth reading before committing to it.

Selected work

Products designed, built, and shipped to real users.

A few apps taken from first idea to store release, relevant to this kind of engagement.

Client feedback

What clients say after shipping.

Verified 5-star reviews from Upwork clients — backed by a Top Rated Plus badge and a 100% job-success record.

Andrii is straightforward to work with; he has shown professionalism from day one and was easily able to understand the tasks before him.
Senior Android dev, ongoing projects · Upwork · ★5.0
Andrii is a very high skilled Android developer, I would definitely work with him again.
Kotlin Multiplatform developer · Upwork · ★5.0

Process

A direct path from first scope to production maintenance.

The workflow stays boring on purpose: define the target, make the technical decisions early, ship in visible increments, and keep the release path clean.

  1. 01

    Scope

    Turn a rough idea into a costed plan — features, milestones, and a realistic timeline.

  2. 02

    Architect

    Design a structure that stays maintainable as the product and the team grow.

  3. 03

    Build

    Ship production code — native Android, Kotlin Multiplatform, and Compose Multiplatform.

  4. 04

    Ship

    Release to the App Store and Google Play with analytics and crash reporting in place.

  5. 05

    Maintain

    Stay on after launch for fixes, OS updates, and the next round of features.

FAQ

The practical questions for this kind of work.

Is Kotlin Multiplatform production-ready?
Yes, for the layer it is designed for — shared business logic, networking, and data. It is used in production by teams well beyond mine. The caveat is scope: treat it as a way to share logic, not as a guarantee that UI code will be shared too.
Do you need iOS experience to build the iOS side?
The shared Kotlin module reduces the iOS-specific work, but the iOS app still needs a real SwiftUI (or Compose Multiplatform) layer, App Store submission, and platform conventions handled properly — that is part of the engagement, not an afterthought.
Can you migrate an existing native Android app to Kotlin Multiplatform?
Yes — this is the most common starting point. The usual path is extracting the networking and persistence layer into a shared module first, validating it against the existing Android app, then building the iOS app against that same module.
What's the difference between Kotlin Multiplatform and Compose Multiplatform?
Kotlin Multiplatform shares logic only — each platform keeps native UI. Compose Multiplatform goes further and shares the UI layer itself, in Compose, across Android, iOS, and desktop. They compose together; you can use KMP for logic and still write native SwiftUI, or add Compose Multiplatform on top when a shared UI is worth it.
How much of a typical app ends up shared?
In practice, usually 40-70% of the codebase — the networking, data, and business-logic layers — with UI staying platform-native. The exact split depends on how similar the Android and iOS product experiences are meant to be.

Related services

Next step

Send the short version of what you need to ship.

Include where the product is now, what needs to be true in the next release, and which platforms matter. I will respond with the most useful next move.

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