What is Act used for?

Act is a command line tool that runs GitHub Actions workflows on your own machine using Docker, for quick feedback and as a local task runner. It is a good fit for debugging CI workflows before pushing, running project tasks defined as Actions and testing custom GitHub Actions locally.

Yes. Act is open source under the MIT licence. Its source code is on GitHub at nektos/act and is written mainly in Go.

Yes. Act is open source, so the software itself is free to use.

What are some alternatives to Act?

Similar open-source tools in the CI/CD & DevOps category include actionlint, Earthly and GitHub Local Actions. SaaS products in the same category include Blacksmith, Travis CI and Buildkite.

Is Act actively maintained?

Yes. The most recent commit to Act was on 9 August 2026, and the latest release is v0.2.89, published on 1 June 2026. The project has 72k stars on GitHub.

Act: open-source CI/CD & DevOps

About Act

act lets you run your GitHub Actions workflows locally. Instead of committing and pushing every time you tweak a file under .github/workflows to see if it works, you run the workflow on your own computer and get feedback right away. The tool sets up environment variables and the filesystem to match what GitHub provides.

It works by reading your workflow files, working out which actions need to run, and using the Docker API to pull or build the images they need, then running them in containers. The author also suggests using it as a local task runner, replacing a Makefile with workflows you already have. A companion GitHub Local Actions extension for Visual Studio Code lets you manage and run act without leaving the editor.

act is written in Go and MIT licensed, and the project name plays on the phrase think globally, act locally. It is a developer tool that runs entirely on your machine, with Docker as the main requirement, and it suits anyone who writes CI workflows and wants a faster edit and test loop.

Key features

Runs GitHub Actions workflows locally
Uses Docker to mirror the GitHub environment
Fast feedback without pushing commits
Can replace Makefile task running
VS Code extension integration
Single Go binary

Good fit for

→Debugging CI workflows before pushing
→Running project tasks defined as Actions
→Testing custom GitHub Actions locally

Built with: Go
Tags: github-actions; ci; devops; docker; cli; go; testing; local-development

Act: questions and answers

What is Act used for?: Act is a command line tool that runs GitHub Actions workflows on your own machine using Docker, for quick feedback and as a local task runner. It is a good fit for debugging CI workflows before pushing, running project tasks defined as Actions and testing custom GitHub Actions locally.
Is Act open source?: Yes. Act is open source under the MIT licence. Its source code is on GitHub at nektos/act and is written mainly in Go.
Is Act free?: Yes. Act is open source, so the software itself is free to use.
What are some alternatives to Act?: Similar open-source tools in the CI/CD & DevOps category include actionlint, Earthly and GitHub Local Actions. SaaS products in the same category include Blacksmith, Travis CI and Buildkite.
Is Act actively maintained?: Yes. The most recent commit to Act was on 9 August 2026, and the latest release is v0.2.89, published on 1 June 2026. The project has 72k stars on GitHub.