Mill

What it does

Build configuration

Mill supports declarative build.mill.yaml files and object-oriented build definitions.checked 7 Oct 2026

Build speed

The site says Mill caches and parallelizes build tasks and tests, and uses a long-lived daemon to keep the JVM warm.checked 7 Oct 2026

Built-in workflows

Mill documents built-in support for dependency management, testing, linting, packaging, publishing, and web frameworks.checked 7 Oct 2026

Commercial support

Commercial support and services for organizational training, adoption, or maintenance are available by arrangement through [email protected].checked 7 Oct 2026

Community support

The site points users to GitHub Discussions and the Scala Discord TOOLING#mill channel for community discussion.checked 7 Oct 2026

Declarative configuration

The site describes build.mill.yaml files as declarative project configuration that can be much shorter than Maven pom.xml files.checked 7 Oct 2026

Dependency management

Mill supports dependency declarations, version management and BOMs, unmanaged dependencies, and JVM version management.checked 7 Oct 2026

IDE limitation

The documentation says VSCode integration supports Java and Scala, while Kotlin users are advised to use IntelliJ IDEA Community Edition.checked 7 Oct 2026

IDE support

Mill supports IntelliJ and VSCode, and generally supports clients of the Build Server Protocol; it can also generate Eclipse project files for Java.checked 7 Oct 2026

Installation

The recommended installation method is a per-project bootstrap script that downloads the selected Mill version when needed.checked 7 Oct 2026

Integrations

The documentation lists integrations including JUnit, ScalaTest, MUnit, Spring Boot, Micronaut, Ktor, Maven Central, Artifactory, Docker, and Apache Spark.checked 7 Oct 2026

JVM requirements

The native launcher can run without Java installed, while the JVM launcher requires a globally installed Java version 17 or newer.checked 7 Oct 2026

Languages

The documented languages include Java, Kotlin, and Scala.checked 7 Oct 2026

Operating systems

The native launcher supports Windows, macOS, and Linux on Intel, and macOS and Linux on ARM; Windows ARM is unsupported by the native launcher.checked 7 Oct 2026

Performance

Mill says it caches and parallelizes build tasks and tests, uses a long-lived daemon, and supports selective test execution.checked 7 Oct 2026

Purpose

Mill is a build tool for Java, Scala, and Kotlin projects.checked 7 Oct 2026

Security

The documentation recommends providing publishing credentials through environment variables for security considerations.checked 7 Oct 2026

Selective test execution

Mill can limit tests and other tasks to those affected by code changes, which the documentation describes as useful for large codebases and CI.checked 7 Oct 2026

Testing

The site lists support for JUnit 4 and 5, TestNG, ScalaTest, Specs2, and MUnit, among other test frameworks.checked 7 Oct 2026