What Is Jetpack Compose, and What Does It Mean for Your Android App?
Old Android screens were like building furniture from a printed manual and a separate box of parts. Compose is like building with LEGO: each piece snaps onto the next, and you can see the shape as you go.
What Jetpack Compose is
Jetpack is Google's collection of helper libraries for Android developers. Compose is the part of Jetpack that builds the user interface, which means the screens, buttons, lists and text people see.
Compose became stable in 2021, and Google now recommends it for building new Android screens. It is free, open source and written for the Kotlin language.
How Compose works
Before Compose, Android screens were drawn in separate layout files written in XML, a kind of structured text. The developer then wrote Kotlin or Java code to find each part of the screen and change it by hand. Two files for one screen, and lots of room for them to fall out of step.
Compose puts everything in one place. Developers write small building blocks, called composables, in Kotlin. Each one describes a piece of the screen, like "a card with a photo and a price". When the data changes, for example the price drops, Compose redraws only that card. The developer does not need to track every change by hand.
Android Studio, Google's free tool for Android development, shows live previews of these building blocks, so the team can check a screen in dark mode or on a tablet without running the full app.
What Compose is good for
- New native Android apps, where it is now the standard choice.
- Design systems: your colors, fonts and button styles can be defined once and reused everywhere.
- Animations and custom designs, which are much simpler than in the old system.
- Adding modern screens to an older app, since Compose and old XML screens can work together.
- Phones, tablets, foldables, Wear OS watches and Android TV, which all have Compose support.
When Compose is not the answer
- You need iOS as well and want one team. Compose on its own is for Android. JetBrains offers Compose Multiplatform for sharing screens with iOS, but it is a younger, less common route than Flutter or React Native.
- You have a big, stable XML app that works fine. Rewriting it only for Compose rarely pays off; add Compose to new screens instead.
- Your team has no Kotlin skills. Compose requires Kotlin.
Compose vs the old XML way
| Jetpack Compose | XML layouts (Views) | |
|---|---|---|
| Where screens are written | Kotlin code only | XML files plus Kotlin or Java |
| Updating the screen | Automatic when data changes | Manual |
| Amount of code | Usually less | Usually more |
| Google's recommendation for new screens | Yes | Still supported |
| Previews | Built in, per building block | Basic |
If you are planning iPhone screens too, the iOS cousin of Compose is SwiftUI. Both use the same "describe the screen" idea, which makes life easier for teams building two native apps.
What it means for cost and timeline
For a new Android app, Compose generally means faster screen building and easier design changes. Less code also means fewer places for layout bugs to hide, which helps quality as the app grows.
For an existing app, the cheapest path is gradual. Build new features in Compose, and update old screens only when you would be touching them anyway. That avoids paying for a rewrite that users never notice.
Ask your team which minimum Android version the app will support. Compose works on a wide range of Android versions, but the choice still affects testing time, because older phones are slower and need extra checks.
Hiring is not hard. Compose is the modern standard, so Android developers who keep their skills current already use it daily.
How Appryze uses Jetpack Compose
On native Android builds, our team writes new screens in Kotlin with Compose. You get weekly written updates, and the code, Google Play account and ad accounts stay in your name. Learn more about our app development work, or see Google's Compose documentation.
Common questions
Is Jetpack Compose the same as Kotlin?
No. Kotlin is the programming language. Jetpack Compose is a toolkit, written in Kotlin, for building Android screens. You need Kotlin to use Compose, but you can use Kotlin without Compose, for example for the logic behind the screens.
Should I rewrite my old Android app in Compose?
Usually not all at once. Compose works alongside the older XML screens in the same app, so a gradual move is normal. Build new features in Compose and update older screens when you are changing them anyway. A full rewrite is only worth it for other strong reasons.
Does Jetpack Compose work on iPhone?
Google's Jetpack Compose is for Android. JetBrains makes a related project, Compose Multiplatform, that can share screens with iOS and desktop. It is a real option, but most teams wanting one codebase for both stores still choose Flutter or React Native.
Is Compose free?
Yes. Jetpack Compose is open source and free, and Android Studio, the tool developers use to build with it, is also free. Your costs are the developers' time and the one-time Google Play developer registration fee.
Tell us what you're building. You get a written scope, timeline and fixed price — plus free Google Play and App Store submission and one month of launch marketing with every build.
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