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GitHub Action to install Crystal programming language and Shards package manager.

Works on Ubuntu, macOS, Windows.


Configurator: get a pre-made config for your exact use case!


  - uses: crystal-lang/install-crystal@v1
  - run: crystal eval "puts 1337"
  - uses: actions/checkout@v4
  - uses: crystal-lang/install-crystal@v1
      crystal: 1.11
  - run: shards install
  - run: crystal spec
      fail-fast: false
          - {os: ubuntu-latest, crystal: latest}
          - {os: ubuntu-latest, crystal: nightly}
          - {os: macos-latest}
          - {os: windows-latest}
    runs-on: ${{matrix.os}}
      - uses: crystal-lang/install-crystal@v1
          crystal: ${{matrix.crystal}}
      - uses: actions/checkout@v4
      - run: shards install
      - run: crystal spec
      - run: crystal tool format && git diff --exit-code
        if: matrix.crystal == 'latest'

Find usages in the wild!

Alternatively, you can use the container-based approach as in the starter workflow (without this action), but the advantage here is the unified approach to installation across 3 systems. Using a custom container has disadvantages on its own, too.



    • crystal: 1.1.0, crystal: 1.2

      Install a particular release of Crystal (if the full version is specified), or the latest patch version of a release series.

    • crystal: latest (default)

      Install the latest released version of Crystal.

    • crystal: nightly

      Install Crystal from the latest continuous build on crystal.git master.

    • crystal: "branch:foo/bar"

      Install Crystal from the latest maintenance build on crystal.git branch specified after branch:.

    • shards: true (default)

      Ensure that some released version of Shards is available. This uses the build that's bundled with Crystal's releases. Other options are slower, as building Shards is a necessary step then.

    • shards: false

      Ensure that shards executable is not available.

    • shards: latest

      Build and install the latest released version of Shards.

    • shards: 0.14.0, shards: 0.16

      Build and install a particular release of Shards (if the full version is specified), or the latest patch version of a release series.

    • shards: nightly

      Build and install the latest commit of shards.git master.

  • arch: x86_64, arch: x86 (defaults to current OS arch)

    The architecture of the build of Crystal to download.

  • destination: some/path

    The directory to store Crystal in, after extracting. Will directly affect outputs.path (the default is in a temporary location).

  • annotate: true (default)

    Display compilation and spec errors as GitHub code annotations.

  • token: ${{ github.token }}

    Personal access token (auto-populated).


  • crystal (${{ steps.some_step_id.outputs.crystal }})

    The actual version of Crystal (as a ref in crystal-lang/crystal.git) that was installed.

  • shards (${{ steps.some_step_id.outputs.shards }})

    The actual version of Shards (as a ref in crystal-lang/shards.git) that was installed.

  • path (${{ steps.some_step_id.outputs.path }})

    The path where Crystal was extracted to, so you can use '[path]/bin/crystal', '[path]/src' etc.