CI/CD for Kotlin: Setting Up a Pipeline from Scratch on a Real Project

You've written a cool project in Kotlin. But how do you deliver updates without pain?

You committed the code, pushed it to GitHub, and… started the manual ritual: build a jar, upload to the server, restart, check that nothing crashed. Sound familiar? And if the project grows, with tests, linters, multiple environments — the routine eats up hours, and one forgotten command can crash production.

There is a solution — CI/CD pipeline for Kotlin. It's an automated pipeline that builds the project, runs tests, checks code style, and deploys to the server after every push. In this article, I'll show you how to set up such a pipeline from scratch using GitHub Actions and Gradle. You'll get a ready-made template that you can adapt to your project — whether it's a server application on Ktor, an Android app, or a library.

Let's go! 🚀

What is CI/CD and why does a Kotlin developer need it?

CI (Continuous Integration) — you push code, and the system automatically builds, tests, and checks quality. CD (Continuous Delivery/Deployment) — after a successful build, the code automatically goes to the server (or app store).

For Kotlin projects, CI/CD is especially important:

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• Saves time — no need to manually run gradle build.
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• Code quality — tests and linters run on every commit.
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• Safety — production is updated only after a green pipeline.
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• Transparency — the whole team sees the build status.
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Today we'll build a full CI/CD pipeline for Kotlin on GitHub Actions. It's free for public repositories and very flexible.

Step 1. Preparing the Kotlin Project

Before writing the pipeline, make sure your project is ready for CI/CD. I'll use a typical structure with Gradle (Kotlin DSL).

Here's an example build.gradle.kts for a simple console application:

plugins {\n    kotlin("jvm") version "1.9.22"\n    application\n}\n\napplication {\n    mainClass.set("com.example.MainKt")\n}\n\nrepositories {\n    mavenCentral()\n}\n\ndependencies {\n    implementation(kotlin("stdlib"))\n    testImplementation("org.jetbrains.kotlin:kotlin-test")\n}\n\ntasks.test {\n    useJUnitPlatform()\n}

Important: add at least one test so the pipeline has meaning.

Example test (src/test/kotlin/com/example/AppTest.kt):

import kotlin.test.Test\nimport kotlin.test.assertEquals\n\nclass AppTest {\n    @Test\n    fun testGreeting() {\n        assertEquals("Hello, Kotlin!", getGreeting())\n    }\n}

Now commit and push the project to GitHub.

Step 2. Creating the First CI Pipeline: Build and Tests

In the root of the repository, create a folder .github/workflows and inside it a file ci.yml.

Here's a minimal GitHub Actions workflow for Kotlin:

name: CI Pipeline for Kotlin\n\non:\n  push:\n    branches: [ main, develop ]\n  pull_request:\n    branches: [ main ]\n\njobs:\n  build:\n    runs-on: ubuntu-latest\n\n    steps:\n      - name: Checkout code\n        uses: actions/checkout@v4\n\n      - name: Set up JDK 17\n        uses: actions/setup-java@v4\n        with:\n          java-version: '17'\n          distribution: 'temurin'\n\n      - name: Grant execute permission for gradlew\n        run: chmod +x gradlew\n\n      - name: Build with Gradle\n        run: ./gradlew build\n\n      - name: Run tests\n        run: ./gradlew test\n\n      - name: Archive test results\n        if: always()\n        uses: actions/upload-artifact@v4\n        with:\n          name: test-results\n          path: build/reports/tests/

What's happening here:

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• Triggers: push