rules_kmp

Bazel rules for Kotlin Multiplatform. A kmp_library builds a module's common and platform source sets for the JVM, Android, Apple platforms (Kotlin/Native) and JS/Wasm, and runs its tests on each platform.

Status: early. The rules come from the Bazel build of a large Kotlin Multiplatform monorepo, where they build every module, but they have seen little use outside it. Expect breaking changes.

What's in it

• kmp_library: a multiplatform module laid out as in Gradle (src/<sourceSet>/kotlin), with Kotlin's default source set hierarchy and tests per platform.
• kmp_jvm_module, kmp_jvm_library, kmp_jvm_test: plain Kotlin/JVM.
• kmp_native_framework, kmp_cinterop, kmp_native_test: Kotlin/Native for iOS and macOS, with Apple frameworks, C and Objective-C interop, and tests on the host or an iOS simulator.
• kmp_compiler_plugin, kmp_ksp: compiler plugins and KSP.
• A Maven extension that pins third-party libraries for each platform. bazel run @maven//:pin resolves the declared artifacts with Gradle, which picks the right variant of each library for each platform (klibs for Kotlin/Native, AARs for Android), and writes a lock file.

Kotlin version

Each release supports exactly one Kotlin version: currently 2.4.21 (KOTLIN_VERSION in kotlin/version.bzl).

Requirements

• Bazel 9.
• macOS with Xcode for the Apple targets.
• An Android SDK for the Android targets.

Getting started

rules_kmp is not on the Bazel Central Registry yet. Depend on a commit:

bazel_dep(name = "rules_kmp")
git_override(
    module_name = "rules_kmp",
    remote = "https://github.com/voize-gmbh/rules_kmp.git",
    commit = "<commit>",
)

examples/basic is a complete workspace: a library for the JVM, Android, iOS and macOS that uses kotlinx-coroutines and kotlinx-serialization, with its tests. Its README has the commands.

License

Apache License 2.0. See LICENSE and NOTICE.