Thirdparty Plugins

The Plugins in this section are developed/maintained outside the mill git tree. This list is most likely not complete. If you’re missing an external plugin or developed one which is not listed here, please open a pull request and add that plugin with a short description.

For details about including plugins in your read Using Mill Plugins.

Besides the documentation provided here, we urge you to consult the respective linked plugin documentation pages. The usage examples given here are most probably incomplete and sometimes outdated!


ANTLR parser generator support for mill.


import $ivy.`net.mlbox::mill-antlr:0.1.0`
import net.mlbox.millantlr.AntlrModule

object foo extends ScalaModule with AntlrModule {
  override def antlrGrammarSources = T.sources {


AspectJ compiler support for mill.


import mill._
import mill.scalalib._
import mill.define._

// Load the plugin from Maven Central via ivy/coursier
import $ivy.`de.tototec::de.tobiasroeser.mill.aspectj_mill0.9:0.3.1-12-89db01
import de.tobiasroeser.mill.aspectj._

object main extends AspectjModule {

  // Select the AspectJ version
  def aspectjVersion = "1.9.5"

  // Set AspectJ options, e.g. the language level and annotation processor
  // Run `mill main.ajcHelp` to get a list of supported options
  def ajcOptions = Seq("-8", "-proc:none")


For documentation, please refer to the project home page.

Bash Completion

Limited bash completion support.


Show transitive dependencies of your build in your browser.


import $ivy.`com.github.ajrnz::mill-dgraph:0.2.0`
sh> mill plugin.dgraph.browseDeps(proj)()


Create an .ensime file for your build.


import mill._
interp.repositories() =
  interp.repositories() ++ Seq(coursier.MavenRepository(""))


import $ivy.`com.github.yyadavalli::mill-ensime:0.0.2`

You can then run the following to generate the .ensime file

mill fun.valycorp.mill.GenEnsime/ensimeConfig

Optionally, you can specify the ensime server version using the –server flag like

mill fun.valycorp.mill.GenEnsime/ensimeConfig --server "3.0.0-SNAPSHOT"


A git version plugin for mill.

import $ivy.`com.goyeau::mill-git:<latest version>`
import com.goyeau.mill.git.GitVersionedPublishModule
import mill.scalalib.JavaModule
import mill.scalalib.publish.{Developer, License, PomSettings, VersionControl}

object `jvm-project` extends JavaModule with GitVersionedPublishModule {
  override def pomSettings = PomSettings(
    description = "JVM Project",
    organization = "com.goyeau",
    url = "",
    licenses = Seq(License.MIT),
    versionControl = VersionControl.github("joan38", "mill-git"),
    developers = Seq(Developer("joan38", "Joan Goyeau", ""))
> mill show jvm-project.publishVersion
[1/1] show
[2/2] com.goyeau.mill.git.GitVersionModule.version

Integration Testing Mill Plugins

Integration testing for mill plugins.


We assume, you have a mill plugin named mill-demo

import mill._, mill.scalalib._
object demo extends ScalaModule with PublishModule {
  // ...

Add a new test sub-project, e.g. itest.

import $ivy.`de.tototec::de.tobiasroeser.mill.integrationtest_mill0.9:0.4.0`
import de.tobiasroeser.mill.integrationtest._

object demo extends ScalaModule with PublishModule {
  // ...

object itest extends MillIntegrationTestModule {

  def millTestVersion = "0.9.3"

  def pluginsUnderTest = Seq(demo)


Your project should now look similar to this:

+-- demo/
|   +-- src/
+-- it/
    +-- src/
        +-- 01-first-test/
        |   +--
        |   +-- src/
        +-- 02-second-test/

As the buildfiles in your test cases typically want to access the locally built plugin(s), the plugins publishes all plugins referenced under pluginsUnderTest to a temporary ivy repository, just before the test is executed. The mill version used in the integration test then used that temporary ivy repository.

Instead of referring to your plugin with import $ivy.'your::plugin:version', you can use the following line instead, which ensures you will use the correct locally build plugins.

import $exec.plugins

Effectively, at execution time, this line gets replaced by the content of, a file which was generated just before the test started to execute.

Please always refer to the official plugin documentation site for complete and up-to-date information.

JaCoCo - Code Coverage

Mill plugin to collect test coverage data with JaCoCo and generate reports.


Create static sites/blogs with JBake.

JBake home:


import mill._
import $ivy.`de.tototec::de.tobiasroeser.mill.jbake:0.1.0`
import de.tobiasroeser.mill.jbake._

object site extends JBakeModule {

  def jbakeVersion = "2.6.4"


Generate the site:

bash> mill site.jbake

Start a local Web-Server on Port 8820 with the generated site:

bash> mill site.jbakeServe


This is a mill module similar to BuildInfo but for Java. It will generate a Java class containing information from your build.

To declare a module that uses this plugin, extend the com.github.carueda.mill.JBuildInfo trait and provide the desired information via the buildInfoMembers method:

import $ivy.`com.github.carueda::jbuildinfo:0.1.2`
import com.github.carueda.mill.JBuildInfo
import mill.T

object project extends JBuildInfo {
  def buildInfoMembers: T[Map[String, String]] = T {
      "name" -> "some name",
      "version" -> "x.y.z"

This will generate:

public class BuildInfo {
  public static final String getName() { return "some name"; }
  public static final String getVersion() { return "x.y.z"; }

Configuration options

  • def buildInfoMembers: T[Map[String, String]]

The map containing all member names and values for the generated class.

  • def buildInfoClassName: String, default: BuildInfo

The name of the class that will contain all the members from buildInfoMembers.

  • def buildInfoPackageName: Option[String], default: None

The package name for the generated class.


Kotlin compiler support for mill.


// Load the plugin from Maven Central via ivy/coursier
import $ivy.`de.tototec::de.tobiasroeser.mill.kotlin_mill0.9:0.2.0`

import mill._
import mill.scalalib._
import mill.define._

import de.tobiasroeser.mill.kotlin._

object main extends KotlinModule {

  // Select the Kotlin version
  def kotlinVersion = "1.4.21"

  // Set additional Kotlin compiler options, e.g. the language level and annotation processor
  // Run `mill main.kotlincHelp` to get a list of supported options
  def kotlincOptions = super.kotlincOptions() ++ Seq("-verbose")



For documentation please visit the mill-kotlin project page.

You will find there also a version compatibility matrix.

Mill Wrapper Scripts

Small script to automatically fetch and execute mill build tool.

How it works

millw is a small wrapper script around mill and works almost identical to mill. It automatically downloads a mill release into $HOME/.mill/download.

The mill version to be used will be determined by the following steps. The search ends, after the first step that results in a version.

  • If the first parameter is --mill-version, the second parameter will be used as the mill version. Example

` sh $ mill --mill-version 0.3.6 --disable-ticker version 0.3.6 `

  • If there is a file .mill-version in the working directory, it’s content will be used as mill version. The file must have only a mill version as content, no additional content or comments are supported. Example

` sh $ echo -n "0.3.6" > .mill-version sh $ mill --disable-ticker version 0.3.6 `

The values of the DEFAULT_MILL_VERSION variable inside the script will be used.

Use cases

As mill executable

Istead of installing mill, you can just place the script into you local $HOME/bin directory and rename it to mill.

If you need a special mill version in a project directory, just place a .mill-version file with the best mill version. Example: setting mill 0.3.6 as best local mill version

sh $ echo -n "0.3.6" > .mill-version

As a wrapper script in your project

To make the start for others easier or to always have the correct mill version in your CI environment, you can just place a copy of the script as millw in your project root directory.

You should change the DEFAULT_MILL_VERSION variable in that script to the correct version you want to use and add the file under version control.


Check binary compatibility with mill.


Just mix-in the Mima trait into your ScalaModule. And set the previous artifacts you want to check binary compatibility.

import mill._, scalalib._

import $ivy.`com.github.lolgab::mill-mima_mill0.9:0.0.2`
import com.github.lolgab.mill.mima._

object main extends ScalaModule with Mima {

  def mimaPreviousArtifacts = Agg(

  // other settings ...


You can then check the binary compatibility of the module with:

> mill main.mimaReportBinaryIssues
Binary compatibility check passed.


Produce OSGi Bundles with mill.


import mill._, mill.scalalib._
import $ivy.`de.tototec::de.tobiasroeser.mill.osgi:0.0.5`
import de.tobiasroeser.mill.osgi._

object project extends ScalaModule with OsgiBundleModule {

  def bundleSymbolicName = "com.example.project"

  def osgiHeaders = T{ super.osgiHeaders().copy(
    `Export-Package`   = Seq("com.example.api"),
    `Bundle-Activator` = Some("com.example.internal.Activator")

  // other settings ...



Since Mill 0.6.1-27-f265a4 there is a built-in publishM2Local target in PublishModule.

Mill plugin to publish artifacts into a local Maven repository.


Just mix-in the PublishM2Module into your project. PublishM2Module already extends mill’s built-in PublishModule.


import mill._, scalalib._, publish._

import $ivy.`de.tototec::de.tobiasroeser.mill.publishM2:0.0.1`
import de.tobiasroeser.mill.publishM2._

object project extends PublishModule with PublishM2Module {
  // ...

Publishing to default local Maven repository

> mill project.publishM2Local
[40/40] project.publishM2Local
Publishing to /home/user/.m2/repository

Publishing to custom local Maven repository

> mill project.publishM2Local /tmp/m2repo
[40/40] project.publishM2Local
Publishing to /tmp/m2repo


Scalafix support for mill.

Fix sources

import $ivy.`com.goyeau::mill-scalafix:<latest version>`
import com.goyeau.mill.scalafix.ScalafixModule
import mill.scalalib._

object project extends ScalaModule with ScalafixModule {
  def scalaVersion = "2.12.11"
> mill project.fix
[29/29] project.fix
/project/project/src/MyClass.scala:12:11: error: [DisableSyntax.var] mutable state should be avoided
  private var hashLength = 7
1 targets failed
project.fix A Scalafix linter error was reported

VCS Version

Mill plugin to derive a version from (last) git tag and edit state. It may support other VCS as well.

Lots of formatting options are provided. When used with its defaults, the outcome is identical to the version scheme used by mill.


import mill._
import mill.scalalib._

// Load the plugin from Maven Central via ivy/coursier
import $ivy.`de.tototec::de.tobiasroeser.mill.vcs.version::0.1.2`
import de.tobiasroeser.mill.vcs.version.VcsVersion

object main extends JavaModule with PublishModule {
  override def publishVersion: T[String] = VcsVersion.vcsState().format()