Installation¶

When a public release is available, use Maven Central. For development builds, add the public GitHub Pages Maven repository and pin the commit-derived version:

// settings.gradle.kts
dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        mavenCentral()
        maven("https://shusek.github.io/kotlin-runtime-web-assembly/maven")
    }
}

Use the BOM so all modules stay on the same version:

// build.gradle.kts
val runtimeVersion = "0.3.0-dev.<12-character-commit>"

dependencies {
    implementation(platform("uk.shusek.krwa:bom:$runtimeVersion"))
    implementation("uk.shusek.krwa:runtime")
    implementation("uk.shusek.krwa:wasi")
    implementation("uk.shusek.krwa:component-model")
    implementation("uk.shusek.krwa:wasi-preview3")
}

runtime already depends on wasm; add wasm directly only when you need the parser/model APIs without the runtime.

component-model is the lightweight runtime dependency and does not ship the embedded wasm-tools.wasm executable. JVM applications that call WIT normalization, component packaging/unbundling, or WasmPlugin.builderFromComponent(...) must opt into tooling:

dependencies {
    implementation("uk.shusek.krwa:component-model-tooling")
}

The uk.shusek.krwa.component-model Gradle plugin includes this tooling artifact automatically. A host that loads a core module with WasmPlugin.builder(witPackage).withModule(module) needs only component-model.

Kotlin Multiplatform¶

In Kotlin Multiplatform builds, put portable dependencies in commonMain.dependencies:

kotlin {
    jvm()
    iosArm64()
    iosSimulatorArm64()
    wasmJs {
        browser()
    }

    sourceSets {
        commonMain.dependencies {
            implementation(project.dependencies.platform("uk.shusek.krwa:bom:$runtimeVersion"))
            implementation("uk.shusek.krwa:runtime")
        }
    }
}

The portable artifacts publish JVM, iOS ARM, and Kotlin/Wasm browser variants. The iOS target set is ARM-only: iosArm64 for devices and iosSimulatorArm64 for Apple Silicon simulators. The web target is Kotlin/Wasm browser (wasmJs { browser() }), not classic Kotlin/JS.

Runtime Engines¶

KRWA no longer ships a Kotlin fallback execution engine. JVM, Android, and iOS execution require a Wasmtime-backed platform engine. On desktop JVM, the built-in FFM bridge loads the Wasmtime C API from krwa.wasmtime.library, KRWA_WASMTIME_LIBRARY, or common system library locations and requires JVM native access. Android and iOS embedders should link and install their platform Wasmtime provider before instantiating modules.

The wasmJs target does not need a backend selector: Instance.builder(module) uses the browser or Node WebAssembly engine through ExecutionBackend.AUTO. Use the wasmJs-only WasmJsExecution facade only when host code needs native wrapper objects for globals, tables, tags, or shared imports.

Local Checkout¶

For local changes that are not committed yet, keep this repository checked out next to your application and use a Gradle composite build:

// settings.gradle.kts
pluginManagement {
    repositories {
        gradlePluginPortal()
        mavenCentral()
    }
}

dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        mavenCentral()
    }
}

includeBuild("../kotlin-runtime-web-assembly")

If you prefer local Maven artifacts, publish the checkout once and enable mavenLocal() in the consuming build:

git clone https://github.com/Shusek/kotlin-runtime-web-assembly.git
cd kotlin-runtime-web-assembly
./gradlew publishToMavenLocal