act
Runs your GitHub Actions workflows on your own computer using Docker.
- Stars
- 72.5k
- Forks
- 2.1k
- Licence
- MIT
- Language
- Go
- Last update
- 5 days ago
- Type
- Dev tool
What it is
act is a command-line tool that reads the GitHub Actions workflow files in your repository (.github/workflows/) and runs them locally instead of on GitHub. It uses the Docker API to pull or build the needed images and run each job in a container, with environment variables and filesystem layout set to match GitHub's. People use it to test workflow changes without committing and pushing each time.
- Test a change to a workflow file without pushing a commit to GitHub
- Run a build or test job locally as a replacement for Makefile targets
- Check how job dependencies and execution order behave before pushing
- Try workflows from a sample repository linked in the README
Great for
- Developers who edit .github/workflows files and want faster feedback than commit-and-push cycles
- Teams who want to reuse their GitHub Actions definitions as a local task runner in place of a Makefile
- People comfortable running Docker on their own machine
Not ideal for
- People without Docker, since the README says the tool uses the Docker API to run containers
- Anyone expecting an exact copy of GitHub's hosted runners, because the README says it matches environment variables and filesystem but does not claim full equivalence
- Users who need workflows that depend on GitHub-hosted services; the README does not describe how those behave locally
How to get it
- 1
Install with a package manager
You'll need: Docker · Go (version listed in go.mod, currently 1.26.0), only if building from source
Clone the repository
git clone git@github.com:nektos/act.gitBuild and install from source
make install - 2
Run it
- Install Docker and make sure it is running
- Install act, either from a release binary or by building from source
- Open a repository that contains .github/workflows/ files
- Run act from the repository root to execute the workflows locally
- 3
Get the most out of it
- Use the act user guide at nektosact.com for configuration and options
- Try the GitHub Local Actions VS Code extension to run workflows from your editor, as the README mentions
- Run make test-fast for tests that do not need Docker if you are contributing
Downloads
Strengths
- Shortens the feedback loop when changing GitHub Actions workflows
- Reuses existing workflow files instead of maintaining a separate local script
- Free and open source under the MIT license
Trade-offs
- Requires Docker, which adds setup and resource use
- The README says local runs only approximate GitHub's environment, so results may differ
- Documentation is in an external user guide, and the README itself is brief
How it compares
| Project | Stars | Type | Level | Updated | Best for |
|---|---|---|---|---|---|
| act (this) | 72.5k | Dev tool | intermediate | 5 days ago | Developers who edit .github/workflows files and want faster feedback than commit-and-push cycles |
| gitea | 58.8k | App | intermediate | 4 days ago | Teams that want to host their own code instead of using a public cloud service |
| semaphore | 14.4k | App | intermediate | 4 days ago | Teams that have outgrown running Ansible or Terraform from a personal terminal |
| floci | 27.7k | Dev tool | beginner | 4 days ago | Developers who want to test AWS code locally without cloud costs |
| task | 16.3k | Dev tool | beginner | 4 days ago | Developers who want a simpler alternative to Makefiles for project scripts |
| goreleaser | 16.1k | Dev tool | intermediate | 4 days ago | Go developers who want to publish command-line tools or binaries for several operating systems |
Stats synced from GitHub. The assessment above was drafted with AI from the project's README on 2026-10-29 and may miss recent changes — check the README before relying on a command. MIT licence: free to use, modify and distribute, including commercially, as long as you keep the copyright notice.