Kotlin Multiplatform Support

AspectK is built for Kotlin Multiplatform from the ground up. The compiler plugin and runtime library support all major Kotlin targets.

Supported Platforms

Platform	Target	Tier
JVM	jvm	—
Android JVM	android	—
JavaScript (IR)	js	—
WebAssembly/JS	wasmJs	—
macOS ARM64	macosArm64	Native Tier 1
macOS x64	macosX64	Native Tier 1
iOS ARM64	iosArm64	Native Tier 1
iOS Simulator ARM64	iosSimulatorArm64	Native Tier 1
iOS x64	iosX64	Native Tier 1
Linux x64	linuxX64	Native Tier 1
Linux ARM64	linuxArm64	Native Tier 2
Windows x64	mingwX64	Native Tier 2
watchOS / tvOS	Various	Native Tier 2
Android Native	arm32/arm64/x86/x64	Native Tier 3

Setup for KMP

// build.gradle.kts
plugins {
    kotlin("multiplatform")
    id("io.github.mole-labs.aspectk.compiler") version "LATEST_VERSION"
}

kotlin {
    jvm()
    iosArm64()
    iosSimulatorArm64()
    js(IR) { browser() }
}

The AspectK Gradle plugin automatically activates the compiler plugin for all configured targets and adds aspectk-runtime as a dependency. No per-target configuration is required.

Shared Aspects Across Platforms

Define your aspects in commonMain as a regular object — they compile and run on every platform:

// commonMain
@Aspect
object CommonLoggingAspect {
    @Before(target = [Logged::class])
    fun log(joinPoint: JoinPoint) {
        println("[${joinPoint.signature.methodName}] called")
    }
}

Platform-Specific Advice

Use expect/actual for platform-specific behavior. Annotate the expect declaration — the annotation propagates to all actual implementations and AspectK intercepts each of them:

// commonMain
@Target(AnnotationTarget.FUNCTION)
annotation class Traced

// Target function — @Traced on the expect declaration propagates to all actuals
@Traced
expect fun fetchData(endpoint: String): String

// commonMain — aspect intercepts @Traced on all platforms
@Aspect
object TracingAspect {
    @Before(target = [Traced::class])
    fun trace(joinPoint: JoinPoint) = platformLog(joinPoint.signature.methodName)
}

expect fun platformLog(methodName: String)

// jvmMain
actual fun fetchData(endpoint: String): String = httpClient.get(endpoint)
actual fun platformLog(methodName: String) { openTelemetry.startSpan(methodName) }

// iosMain
actual fun fetchData(endpoint: String): String = NSURLSession.data(endpoint)
actual fun platformLog(methodName: String) { OSLog.log(methodName) }

Platform Constraints

Constraint	Details
Reflection (KClass)	Available on all platforms; generic erasure applies everywhere
JoinPoint.target	Always available; null for top-level functions on all platforms
Aspect discovery	Only aspects within the same compilation unit are discovered