Setting Up Compose Multiplatform: From Zero to Hello World

Introduction

Jetpack Compose isn't just for Android anymore. With Compose Multiplatform (CMP), you can write one UI codebase in Kotlin and run it across Android, iOS, and Desktop. In this first part of the series, we'll set up a CMP project using JetBrains' Kotlin Multiplatform Wizard and get it running on Desktop.

Step 1: Generate the Project

Go to Kotlin Multiplatform Wizard.

Select:

• ✅ Android
• ✅ iOS
• ✅ Desktop
• ✅ iOS UI = Compose
• ✅ Include Tests

Click "New Project", download, and open it in IntelliJ IDEA.

Your project will look like this:

shared/
  └── src/
      ├── commonMain/   # shared UI + logic
      ├── androidMain/  # Android-specific
      ├── iosMain/      # iOS-specific
      └── desktopMain/  # Desktop-specific

Step 2: Run on Desktop

In desktopMain/kotlin/Main.kt you'll find:

1fun main() = application {
2    Window(onCloseRequest = ::exitApplication) {
3        Text("Hello, Compose Multiplatform!")
4    }
5}

▶ Run → Your first CMP app opens in a native window.