Introduction

Kargo is Cargo for Kotlin. It is a build tool and package manager that creates, builds, runs and tests Kotlin projects from a single kargo.toml file.

kargo.toml

[package]
name = "hello"
version = "0.1.0"
group = "com.example"

[kotlin]
version = "2.4.21"

[dependencies]
"org.jetbrains.kotlinx:kotlinx-datetime" = "0.7.1"

That is a complete project. There is no build.gradle.kts, no settings.gradle.kts, no wrapper and no plugin block.

What you get

• Four targets. JVM, WebAssembly (js or wasi), Kotlin/Native (Linux, macOS, Windows, iOS and more) and Android. One project can enable several of them and share code between them with expect/actual.
• Maven dependencies. Kargo resolves from Maven Central (plus any repositories you add) and understands POM inheritance, BOMs, exclusions, version ranges, relocations and Gradle module metadata. Kotlin Multiplatform libraries resolve to the right .jar or .klib for each target.
• Reproducible builds. kargo.lock pins every version and the SHA-256 of every downloaded file.
• Incremental compilation. If a target’s sources, classpath and flags have not changed, it is not recompiled. On the JVM, an edit recompiles only the files it affects, in a warm compiler daemon.
• Built-in frameworks. Compose, Ktor, Spring Boot, kotlinx.serialization, coroutines and Lombok each take one line to enable. Kargo adds the libraries, compiler plugins and flags.
• Managed toolchains. Kargo can download a JDK for you, and it installs Kotlin/Native automatically.
• Extensibility. Tasks, build hooks, compiler plugins and kargo-<name> subcommands.

How it works

For the JVM, Wasm, JS and Native targets Kargo does not use Gradle. It downloads the Kotlin compiler (kotlin-compiler-embeddable) and Kotlin/Native (kotlin-native-prebuilt) from Maven Central and calls them directly. That keeps builds fast and keeps everything in one config file.

Android is the one exception. Android builds need the Android Gradle Plugin, so Kargo generates a Gradle project under target/android from your kargo.toml and runs it for you. You still never edit Gradle files.

Who it is for

• People new to Kotlin who want to write code without learning a build system first. Start with Your first Kotlin app.
• Rust developers who already know Cargo’s workflow. See For Rust developers.
• Gradle and Maven users who want something simpler for apps, services, CLIs and libraries. See the migration guides.