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Mobile Development · head to head

Flutter vs Kotlin Multiplatform

Flutter logo

Flutter

Mobile Development

Google’s open-source framework for building apps from one codebase

From
Free
Rated
-
Full reviewWebsite
Kotlin Multiplatform logo

Kotlin Multiplatform

Mobile Development

JetBrains-funded technology for sharing Kotlin business logic across iOS, Android, web, desktop and server

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Flutter dart is used almost nowhere else, so the language itself is a hiring and learning cost; 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.
  • They diverge on capability: Flutter covers Single codebase, many targets, Kotlin Multiplatform covers Shared Kotlin logic.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Flutter and Kotlin Multiplatform actually diverge.

Attributes where Flutter and Kotlin Multiplatform differ
AttributeFlutterKotlin Multiplatform
PlatformsiOS, Android, Web, Windows, macOS, LinuxiOS, Android, Windows, macOS, Linux, Web

Identical on both: starting price (Free), pricing model (Open source, no licence fee), free tier (Yes), user rating (Not yet rated), category (Mobile Development).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Flutter

  • Single codebase, many targets
  • Own rendering engine
  • Hot reload
  • Widget library
  • Ahead-of-time compilation
  • DevTools

Only in Kotlin Multiplatform

  • Shared Kotlin logic
  • Native UI retained
  • Compose Multiplatform (optional)
  • IDE tooling
  • Gradle-based builds
  • Incremental adoption

What people use each for

The jobs each tool is most often brought in to do.

Flutter

  • Shipping one app to iOS and Android with a small teamnot Kotlin Multiplatform
  • Interfaces with heavy custom design that need to look identical on both platformsnot Kotlin Multiplatform
  • Adding web or desktop builds to an existing mobile codebasenot Kotlin Multiplatform
  • Prototyping quickly where hot reload shortens the design loopnot Kotlin Multiplatform

Kotlin Multiplatform

  • A company with existing separate native iOS and Android codebases wanting to stop duplicating business logic and networking codenot Flutter
  • A team that wants shared logic but is not willing to compromise on fully native UI per platformnot Flutter
  • An organisation already using Kotlin on the backend that wants to reuse the same models and validation on mobile clientsnot Flutter
  • A team evaluating Compose Multiplatform for UI sharing but wanting the option to fall back to native UI per screennot Flutter

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Flutter

  • Dart is used almost nowhere else, so the language itself is a hiring and learning cost
  • Because Flutter draws its own widgets, apps can feel subtly unlike the platform unless deliberately styled per-platform
  • Binary sizes are larger than equivalent native apps because the engine ships with the app
  • Access to a brand-new platform API waits on a plugin, or on writing platform channel code yourself

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.

Pricing, plan by plan

Flutter

Free
  • FlutterFree
    • Full framework
    • All platform targets
    • Dart toolchain

Kotlin Multiplatform

Free
  • Kotlin MultiplatformFree
    • 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

Which should you pick?

Choose Flutter if

  • You need single codebase, many targets.
  • You want to start without paying.
  • You work on iOS, Android, Web, Windows, macOS, Linux.
  • You also want own rendering engine.
Flutter review

Choose Kotlin Multiplatform if

  • You need shared kotlin logic.
  • You want to start without paying.
  • You work on iOS, Android, Windows, macOS, Linux, Web.
  • You also want native ui retained.
Kotlin Multiplatform review

Questions people ask

Is Flutter or Kotlin Multiplatform better?
Neither clearly leads. Flutter starts at Free and Kotlin Multiplatform at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Flutter or Kotlin Multiplatform?
Flutter starts at Free and Kotlin Multiplatform at Free.
Does Flutter or Kotlin Multiplatform run on more platforms?
Flutter runs on iOS, Android, Web, Windows, macOS, Linux. Kotlin Multiplatform runs on iOS, Android, Windows, macOS, Linux, Web.
Can I use Flutter for free?
Both have a free tier, so you can try either at no cost before committing.
What is Flutter best used for?
Flutter is most often used for shipping one app to ios and android with a small team, interfaces with heavy custom design that need to look identical on both platforms, adding web or desktop builds to an existing mobile codebase, prototyping quickly where hot reload shortens the design loop. Of those, shipping one app to ios and android with a small team and interfaces with heavy custom design that need to look identical on both platforms are not what Kotlin Multiplatform is typically brought in for.
What can Flutter do that Kotlin Multiplatform cannot?
Flutter covers Single codebase, many targets, Own rendering engine, Hot reload, Widget library. Kotlin Multiplatform covers Shared Kotlin logic, Native UI retained, Compose Multiplatform (optional), IDE tooling.

Answered from the vendors’ own pages

Flutter: Is Flutter free?

Yes. Flutter is open source with no licence fee. The framework is under a Creative Commons Attribution 4.0 licence and its code samples under the 3-Clause BSD licence.

Kotlin Multiplatform: 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.

Flutter: What language does Flutter use?

Dart, a language Google designed for fast startup and ahead-of-time compilation to native code.

Kotlin Multiplatform: Is there a paid version?

No. It is Apache 2.0 licensed and free, funded by JetBrains as part of the Kotlin project.

Flutter: Can Flutter build for more than mobile?

Yes. The same codebase targets iOS, Android, web, Windows, macOS, Linux and embedded devices, though mobile remains the most mature target.

Kotlin Multiplatform: 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.

Flutter: How is Flutter different from React Native?

Flutter draws its own widgets with its own engine, so the result is pixel-identical across platforms. React Native renders to the real native components of each platform. Flutter uses Dart; React Native uses JavaScript and React.

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