A tiny Kotlin Multiplatform (KMP) toast library for Compose Multiplatform (Android + iOS).

iOS has no native toast. This library fills that gap: on iOS it renders a transient overlay in a dedicated UIWindow above normal app content, with the window configured not to receive touch events. On Android it delegates to the native android.widget.Toast.

• ✅ One API, two platforms
• ✅ No non-Compose runtime dependencies
• ✅ Platform-backed presentation

Some KMP toast implementations draw the toast inside the Compose tree (a Popup/overlay). That ties the toast to the composition: it may be covered by native dialogs, and navigation behavior depends on where the overlay is hosted.

CMPToaster takes a different route. The API is Compose-friendly (rememberToast()), but the toast itself is rendered natively:

• iOS — presented on a dedicated UIWindow at UIWindowLevelAlert + 1. So it:
  • can remain visible during common Compose navigation and UIKit transitions
  • is intended to appear above Compose dialogs and standard UIKit alerts / action sheets
  • does not need a Compose host for the toast overlay
• Android — delegates to the native android.widget.Toast.

In short: a Kotlin Multiplatform toast with a Compose-facing API and platform-backed presentation.

Note: the iOS overlay is positioned near the bottom safe area and is not intended to cover the software keyboard. Android keyboard behavior is handled by the native platform toast.

CMPToaster is published to Maven Central. Make sure mavenCentral() is in your repositories, then add the dependency to your shared module.

// settings.gradle.kts
dependencyResolutionManagement {
  repositories {
    mavenCentral()
  }
}

// build.gradle.kts (your shared module)
kotlin {
  sourceSets {
    commonMain.dependencies {
      implementation("com.masaibar:cmp-toaster:1.0.0")
    }
  }
}

import androidx.compose.material3.Button
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import com.masaibar.cmptoaster.ToastDuration
import com.masaibar.cmptoaster.rememberToast

@Composable
fun Demo() {
  val toast = rememberToast()

  Button(onClick = { toast.show("This is a short toast") }) {
    Text("Short toast")
  }

  Button(onClick = { toast.show("This is a long toast", ToastDuration.LONG) }) {
    Text("Long toast")
  }
}

That's the whole API:

expect class Toast {
  fun show(
    message: String,
    duration: ToastDuration = ToastDuration.SHORT
  )
}

enum class ToastDuration { SHORT, LONG }

@Composable
expect fun rememberToast(): Toast

To build the library and run the sample:

The published artifact was built with Kotlin 2.1.21 and Compose Multiplatform 1.8.2. Consumer projects should use compatible Kotlin and Compose Multiplatform versions.

Android	iOS

A runnable Compose Multiplatform sample lives in sample/ (shared UI), with an Android app and an iOS app in iosApp/. It includes:

• Basics — short and long toasts
• Dialog example — show a toast while a Compose AlertDialog is open
• Navigation example — show a toast, then move to another screen

Run it:

• Android — open the repository root in Android Studio and run the sample configuration
• iOS — open iosApp/iosApp.xcodeproj in Xcode and run on a simulator

• android (minSdk 29)
• iosArm64, iosSimulatorArm64

./gradlew :toast:assemble                          # Android
./gradlew :toast:compileKotlinIosSimulatorArm64    # iOS (fast check)

	App	Links
	AdMonitor - Dashboard for AdMob	Google Play / App Store

Using CMPToaster in your app? Feel free to open a PR to add it here!

MIT © masaibar