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coursier/setup-action

▶️ GitHub Action using Coursier to install JVM and Scala tools
Source code at GitHub https://github.com/coursier/setup-action
coursier/setup-action.json
{
  "createdAt": "2020-10-26T00:45:10Z",
  "defaultBranch": "main",
  "description": "▶️ GitHub Action using Coursier to install JVM and Scala tools",
  "fullName": "coursier/setup-action",
  "homepage": "",
  "language": "TypeScript",
  "name": "setup-action",
  "pushedAt": "2026-08-04T16:02:27Z",
  "stargazersCount": 61,
  "topics": [
    "coursier",
    "coursier-setup",
    "github-actions",
    "jvm",
    "scala",
    "setup-scala"
  ],
  "updatedAt": "2026-08-04T16:03:46Z",
  "url": "https://github.com/coursier/setup-action"
}

Coursier setup GitHub Action

Section titled “Coursier setup GitHub Action”

A GitHub Action to install Coursier and use it to install Java and Scala CLI tools.

It can be useful if you want to install a specific version of JVM or use a build tool like mill or seed.

Inspired by olafurpg/setup-scala and the blog post Single command Scala setup by Alex Archambault (author of Coursier).

Features

Section titled “Features”
  • run it on any platform: Linux, MacOS, Windows
  • install any JVM you need
  • setup the build tool of your choice: sbt, mill, seed, etc.
  • install other common Scala CLI tools: Ammonite, Bloop, giter8, etc.

Inputs

Section titled “Inputs”

  • jvm (optional): JVM to install

    • one of the options from cs java --available.
    • if left empty either the existing JVM will be used or Coursier will install its default JVM.

  • jvm-index (optional): The JVM index source

    • arbitrary URL containing the JVM index source like in cs java --available --jvm-index https://url/of/your/index.json.
    • if left empty the coursier index will be used as default JVM index source

  • apps (optional): Scala apps to install (sbtn by default)

  • version (optional): Coursier version to install

    • a release version such as 2.1.25-M26 (defaults to a recent release when left empty)
    • nightly installs the latest nightly build

  • customRepositories (optional): ”

  • disableDefaultRepos (optional): ‘false’

    • Whether or not to pass the —no-default flag to coursier

  • mirrors (optional): ”

    • Newline-separated list of from=to entries written to ~/.config/coursier/mirror.properties before any cs invocation.
    • The from side may be a comma-separated list of source URLs.
    • Unlike customRepositories / disableDefaultRepos, mirrors are applied at the resolver level to every repository coursier sees — including ones declared inside app descriptors that customRepositories cannot override.
    • See coursier mirrors.

  • extraJvmArgs (optional): ”

    • Space-separated list of -D JVM property args passed to every cs invocation. The -J prefix is added automatically if missing.
    • e.g. -Dhttps.proxyHost=proxy.example.com -Dhttps.proxyPort=8080

  • launcher (optional): Coursier launcher

    • Leave empty (default) to install the default native binary launcher when available, or a JVM launcher on platforms that do not have a native launcher.
    • thin (or jvm) selects the thin JVM launcher and assembly selects the assembly (fat JAR) launcher. These require Java to be installed beforehand.
    • Other values select a native launcher flavor. Available flavors include container, compat, and static; for example, container downloads the launcher whose filename ends in -container.
    • The action fails when the selected launcher is not available for the selected version and platform.

  • preferredLauncher (optional): Preferred Coursier launcher flavor

    • Downloads the same launcher as launcher, but falls back to the default launcher with a warning when the flavored download returns a 4xx HTTP response.
    • The JVM launcher values thin, jvm, and assembly are rejected; pass those via launcher.
    • Cannot be used together with launcher.

  • useContainerImage (optional): Deprecated alias for launcher: container.

Example with custom inputs

Section titled “Example with custom inputs”
  steps:
    - uses: actions/checkout@v4
    - uses: coursier/setup-action@v3
      with:
        jvm: adopt:11
        jvm-index: https://url/of/your/index.json
        apps: sbtn bloop ammonite
        disableDefaultRepos: true
        customRepositories: https://packages.corp.com/maven
        mirrors: |
          https://repo1.maven.org/maven2=https://packages.corp.com/maven

Nightly Coursier

Section titled “Nightly Coursier”
  steps:
    - uses: actions/checkout@v4
    - uses: coursier/setup-action@v3
      with:
        version: nightly

Outputs

Section titled “Outputs”
  • cs-version: version of the installed Coursier (should be the latest available)

Caching

Section titled “Caching”

This action should work well with the official Coursier cache-action. For example:

  steps:
    - uses: actions/checkout@v4
    - uses: coursier/cache-action@v8
    - uses: coursier/setup-action@v3