kmp-ci-cd

name	kmp-ci-cd
description	GitHub Actions CI/CD for Kotlin Multiplatform — matrix builds (ubuntu for JVM/Android/JS, macOS for iOS), caching, Maven Central / SPM / CocoaPods publishing. Use when wiring CI or a release pipeline.

KMP CI/CD

Instructions

KMP CI needs both Linux (for Android, JVM, JS, Wasm) and macOS (for iOS). Split the matrix so macOS runners — the expensive ones — only do what they must.

1. Matrix workflow

# .github/workflows/ci.yml
name: CI
on:
  push: { branches: [ main ] }
  pull_request:

concurrency:
  group: ci-${{ github.ref }}
  cancel-in-progress: true

jobs:
  jvm-and-android:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-java@v4
        with: { distribution: temurin, java-version: '17' }
      - uses: gradle/actions/setup-gradle@v4
      - run: ./gradlew :shared:jvmTest :shared:testDebugUnitTest :shared:jsTest --no-daemon --stacktrace

  ios:
    runs-on: macos-14
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-java@v4
        with: { distribution: temurin, java-version: '17' }
      - uses: gradle/actions/setup-gradle@v4
      - run: sudo xcode-select -s /Applications/Xcode_15.4.app
      - run: ./gradlew :shared:iosSimulatorArm64Test --no-daemon --stacktrace
      - run: ./gradlew :shared:assembleSharedReleaseXCFramework --no-daemon

  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-java@v4
        with: { distribution: temurin, java-version: '17' }
      - uses: gradle/actions/setup-gradle@v4
      - run: ./gradlew ktlintCheck detekt --no-daemon

2. Caching

gradle/actions/setup-gradle@v4 already caches the Gradle build cache, configuration cache, and wrapper. For Kotlin/Native, add:

      - name: Cache konan
        uses: actions/cache@v4
        with:
          path: ~/.konan
          key: konan-${{ runner.os }}-${{ hashFiles('**/*.gradle.kts', 'gradle/libs.versions.toml') }}
          restore-keys: konan-${{ runner.os }}-

~/.konan holds the Kotlin/Native toolchain and precompiled platform libs — ~2 GB, but saves 5-10 min per macOS job.

3. Android app build + instrumentation

  android-app:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-java@v4
        with: { distribution: temurin, java-version: '17' }
      - uses: gradle/actions/setup-gradle@v4
      - run: ./gradlew :androidApp:assembleRelease --no-daemon
      - uses: actions/upload-artifact@v4
        with: { name: android-apk, path: androidApp/build/outputs/apk/release/*.apk }

4. Publishing to Maven Central

  publish:
    if: startsWith(github.ref, 'refs/tags/v')
    runs-on: macos-14
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-java@v4
        with: { distribution: temurin, java-version: '17' }
      - uses: gradle/actions/setup-gradle@v4
      - env:
          ORG_GRADLE_PROJECT_mavenCentralUsername: ${{ secrets.OSSRH_USERNAME }}
          ORG_GRADLE_PROJECT_mavenCentralPassword: ${{ secrets.OSSRH_PASSWORD }}
          ORG_GRADLE_PROJECT_signingInMemoryKey: ${{ secrets.SIGNING_KEY }}
          ORG_GRADLE_PROJECT_signingInMemoryKeyPassword: ${{ secrets.SIGNING_KEY_PASSWORD }}
        run: ./gradlew publishAllPublicationsToMavenCentralRepository --no-daemon --no-configuration-cache

Use the vanniktech Maven publish plugin, which handles all KMP publications (kotlinMultiplatform, androidRelease, iosArm64, etc.) out of the box.

5. XCFramework → Swift Package Manager

Publish the release XCFramework as a GitHub release asset and point a Package.swift at it:

// Package.swift in a separate repo my-shared-swift
let package = Package(
    name: "Shared",
    platforms: [.iOS(.v14)],
    products: [.library(name: "Shared", targets: ["Shared"])],
    targets: [
        .binaryTarget(
            name: "Shared",
            url: "https://github.com/me/my-kmp/releases/download/v1.2.3/Shared.xcframework.zip",
            checksum: "…compute via `swift package compute-checksum`…"
        ),
    ]
)

Automate the release:

      - name: Zip XCFramework
        run: |
          cd shared/build/XCFrameworks/release
          zip -r Shared.xcframework.zip Shared.xcframework
      - name: Compute checksum
        id: sum
        run: echo "sum=$(swift package compute-checksum shared/build/XCFrameworks/release/Shared.xcframework.zip)" >> $GITHUB_OUTPUT
      - uses: softprops/action-gh-release@v2
        with:
          files: shared/build/XCFrameworks/release/Shared.xcframework.zip
          body: |
            XCFramework checksum: `${{ steps.sum.outputs.sum }}`

Then open a PR to the SPM repo bumping URL + checksum.

6. CocoaPods publishing (only if consumers still use pods)

      - run: ./gradlew :shared:podPublishReleaseXCFramework --no-daemon
      - run: pod trunk push shared/build/cocoapods/publish/release/Shared.podspec
        env:
          COCOAPODS_TRUNK_TOKEN: ${{ secrets.COCOAPODS_TRUNK_TOKEN }}

7. Release hygiene

• Tag with semver (v1.2.3); the publish workflow keys on tags.
• Fail builds on XCFramework size growth beyond a threshold (e.g. +10%).
• Keep one linting job (ktlintCheck, detekt) required for PR merges.
• Gradle configuration cache should be on in CI; if a publish task breaks it, pass --no-configuration-cache only to that job.

Checklist

• JVM/Android/JS jobs run on ubuntu-latest; iOS on macos-14 (or later).
• ~/.konan cached — macOS jobs noticeably faster.
• Lint + tests required for PR merge.
• Tag-triggered publish job pushes to Maven Central and (if used) SPM / CocoaPods.
• XCFramework zipped and checksummed; SPM Package.swift points to a stable release URL.
• Secrets (signing key, OSSRH, trunk token) stored in GitHub Actions secrets, never in the repo.
• CI matrix cancels on new pushes via the concurrency block.