compose-multiplatform

Compose Multiplatform is a UI framework made by JetBrains that lets you write the visual design of an app once in Kotlin and share it across Android, iOS, desktop (Windows, macOS, Linux), and web — instead of building a separate interface for each platform.

It is based on Jetpack Compose, the modern UI toolkit Google uses for Android apps. You describe what the screen should look like using declarative code (meaning you describe the desired result, not a sequence of steps), and the framework handles the rendering. Because the same UI code runs on multiple targets, you reduce duplication and keep your app's look consistent everywhere. For mobile, it can access native platform APIs like the device camera. For desktop, it renders with hardware-accelerated graphics and supports menus, keyboard shortcuts, and system notifications. Web support (via Kotlin/Wasm — a format that runs near-native-speed code in browsers) is in Beta.

You would use Compose Multiplatform if you are a Kotlin developer building an app that needs to run on more than one platform and you want to avoid writing and maintaining completely separate UIs. It requires Kotlin as the programming language and works well with JetBrains tools.