Kotlin Multiplatformvs
Flutter
Flutter: If you want a single shared UI codebase from day one rather than logic-only sharing
Kotlin Multiplatform
JetBrains-funded technology for sharing Kotlin business logic across iOS, Android, web, desktop and server
As of 1 September 2026, Kotlin Multiplatform is free to use. An Apache 2. Softwr lists it under Mobile Development. Kotlin Multiplatform is made by JetBrains s.r.o., available on iOS, Android, Windows, macOS.
Overview
What Kotlin Multiplatform does
Kotlin Multiplatform (KMP) lets a team write business logic, networking, data models and validation once in Kotlin and compile it natively for iOS, Android, desktop, web and server targets, while each platform keeps its own native UI written in Swift/SwiftUI, Kotlin/Jetpack Compose or other platform-native tooling. This is a deliberately narrower scope than Flutter or React Native: KMP by itself shares logic, not UI. What distinguishes it commercially is that it is entirely free and open source under Apache 2.0, funded by JetBrains as part of the Kotlin language it also stewards, with tooling support built into IntelliJ IDEA and Android Studio at no extra cost. Teams that want to also share UI code add Compose Multiplatform, a separate JetBrains project, on top; that layered structure means a team can start with logic-only sharing and add UI sharing later without re-platforming. Buyers are typically teams that already have native iOS and Android codebases and want to stop duplicating business logic and API clients across Swift and Kotlin, rather than teams starting a mobile app from zero. The trade-off is that adopting KMP does not remove the need for two native UI codebases unless Compose Multiplatform (still less mature on iOS than Flutter's cross-platform rendering) is also adopted, so the "write once" promise is partial by design.
What people use it for
- A company with existing separate native iOS and Android codebases wanting to stop duplicating business logic and networking code
- A team that wants shared logic but is not willing to compromise on fully native UI per platform
- An organisation already using Kotlin on the backend that wants to reuse the same models and validation on mobile clients
- A team evaluating Compose Multiplatform for UI sharing but wanting the option to fall back to native UI per screen
Related searches
The honest half
Where it falls short
Concrete and checkable, so you can decide whether any of them matter to you. This is the half of a review a vendor will not write about Kotlin Multiplatform.
- It shares logic, not UI, by default, so a team expecting a Flutter-style single UI codebase has to also adopt Compose Multiplatform, which is newer and less proven on iOS than on Android.
- iOS interop relies on Kotlin/Native compiling to a framework consumed from Swift, and debugging across that boundary is more friction than debugging pure Swift or pure Kotlin.
- Because logic-sharing is the whole premise, teams still need genuine iOS and Android UI expertise on staff; it does not reduce the native skills bar the way a full cross-platform UI framework aims to.
- Build times and tooling maturity for multiplatform Gradle projects lag behind single-platform Kotlin or Swift projects, and multiplatform-specific build errors are less well documented.
- JetBrains funds it as part of the broader Kotlin investment, so its roadmap priority competes internally with IntelliJ, Android Studio and other JetBrains commitments rather than having dedicated headcount the way Flutter has at Google.
Cross-shopped
What people choose instead of Kotlin Multiplatform
Each pairing was judged by two reviewers asking whether a buyer would genuinely weigh the two against each other. The ones that failed were deleted rather than published.
- Kotlin MultiplatformvsReact Native
React Native: If your team is JavaScript-first rather than Kotlin-first
- Kotlin Multiplatformvs.NET MAUI
.NET MAUI: If your existing codebase is C# rather than Kotlin
Pricing
What Kotlin Multiplatform costs
Taken from the vendor's own pricing page. Prices move, so check before you buy.
Kotlin Multiplatform
Free
- Apache 2.0 licensed, unlimited apps
- IDE tooling in the free Android Studio and free-tier IntelliJ IDEA Community
- No paid Kotlin Multiplatform edition exists
Capabilities
Features
Shared Kotlin logic
Networking, data models, validation and business rules compiled natively per platform
Native UI retained
Each platform keeps SwiftUI, Jetpack Compose or other native UI unless Compose Multiplatform is added
Compose Multiplatform (optional)
A separate JetBrains layer for sharing UI code as well as logic
IDE tooling
First-class support in IntelliJ IDEA and Android Studio, including debugging across shared code
Gradle-based builds
Standard Kotlin/Gradle tooling rather than a new build system
Incremental adoption
Can be introduced into an existing native iOS or Android codebase module by module
Answered, with sources
Questions people ask
Each answer names the page it came from, so you can check it rather than take our word for it.
Does Kotlin Multiplatform replace my native UI code?
Not by default. It shares business logic and data layers; UI stays native per platform unless you separately adopt Compose Multiplatform.
Is there a paid version?
No. It is Apache 2.0 licensed and free, funded by JetBrains as part of the Kotlin project.
Do I need Compose Multiplatform to use it?
No, they are separate. You can share only logic and keep fully native UI on each platform indefinitely.
Keep looking
Where to go from Kotlin Multiplatform
- Kotlin Multiplatform alternativesEvery product people weigh against it
- Kotlin Multiplatform pricingPlans, floors and what the tiers exclude
- Kotlin Multiplatform badgesWhich rules it meets, and the figure behind each
- All Mobile Development softwareThe full category
- Best Mobile Development softwareThe shortlist, and how it was cut
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Compare Kotlin Multiplatform with
- .NET MAUI
- Flutter
- React Native
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- Appcircle
- .NET MAUI
- Android Studio
- Ionic
- Superwall
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Softwr does not host reviews and shows no star rating for Kotlin Multiplatform, because a rating we did not collect is not ours to publish. What is here is the pricing and platform detail from the vendor’s own pages, limitations we could state concretely, and alternatives a reviewer confirmed people weigh against it. Tell us if any of it is wrong.
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Best Mobile Development software alternatives
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Per month by tracked revenue