Comparing the performance of the same app in Flutter, native and Kotlin Multiplatform (KMP) on Android and iOS.

🐈 Sample app

The app will contain a single screen, load cat pictures from a public API and show them in a horizontal list. Each picture can be clicked to show it zoomed in below the list.

📂 Technology overview

Folder	Technology	UI Framework	Network lib	Image lib
/flutter	Cross-platform, Dart	Flutter	http.dart	Built-in image widget
/kmp	Cross-platform, Kotlin	Compose UI Multiplatform	Ktor	Kamel
/native-ios	Native, Swift	SwiftUI	Alamofire	AlamofireImage
/native-android	Native, Kotlin	Compose UI	Ktor	Kamel

📦 Builds

Release builds are available in /builds.

📊 Benchmark results

📦 App size

Android sizes were measured by running Bundletool* on the signed, minified release bundles to create an APK set for a Pixel 4a, and then running get-size on that APK set. iOS sizes were measured running the App Thinning Size report.

Technology	Android	iOS	Remarks
Native (Compose/SwiftUI)	1.463 MB	1.7 MB
KMP (Compose)	1.463 MB	24.8 MB (v1.4) 32.2 MB (v1.5)	Includes Skia on iOS, where Android relies on built-in Skia.
Flutter	6.828 MB	17.9 MB	Also includes Skia on iOS + Flutter framework.

Note: due to https://github.com/Kamel-Media/Kamel/issues/47 the Kamel library isn't being minified. Once that's fixed, the Android native and Android KMP builds will both be smaller.

*commands used:

• bundletool build-apks --connected-device --bundle=release.aab --output=release.apks
• bundletool get-size total --apks=release.apks

🚀 Startup

Android

Android startup benchmarks were executed using Macrobenchmark, 5 times on a Pixel 4a. Test suite was run twice in alternating order.

App	min.	median	max.
Native Android	408.7 ms	413.1 ms	423.1 ms
KMP Android	403.6 ms	425.3 ms	466.4 ms
Flutter Android	600.5 ms	634.2 ms	649.8 ms

iOS

The iOS startup tests were run on an iPhone 12 Mini.

App	Duration (AppLaunch)
Native iOS	1.441 s
KMP iOS	1.618 s
Flutter iOS	1.608 s