72,214 stars · MIT at master/LICENSE, stock text, AND THE HOLDER IS NOT NAMED — the line reads only 'Copyright (c) 2019' with no person or entity. · v0.2.89, '01 Jun' with no year, settled as 1 June 2026 by the ungh releases record (v0.2.88 1 May 2026, v0.2.87 1 Apr 2026 behind it). Code pushed 9 Aug 2026, two months after the release. · Track this in Scout
Runs your GitHub Actions workflows on your own machine inside Docker, so a broken workflow is fixed in seconds rather than in push-and-wait cycles.
▶Repo detailsthe review · specs · pros & cons · install
What it is
GitHub Actions is GitHub's own system for running automatic jobs — tests, builds, checks — whenever code changes. act reads the same workflow files and runs those jobs on your computer inside Docker, which is a way to run a program inside its own sealed box so it cannot break anything else on the machine.
What it is good for. Anyone who has sat waiting for a build to fail on a typo. The loop of push, wait, read the log, fix, push again is the slowest part of fixing a broken workflow, and this removes it. It is most useful to someone who maintains more than one small project and cannot keep a paid build service for each.
- The same workflow file, no second copy to keep in step.
act -llists every job it can see before anything runs.- Nine years old, 72,214 stars, and a release roughly every month.
- It needs Docker installed and running first, which is a real piece of software to learn.
- It is not a real GitHub runner. The small default images leave out most of the tools GitHub preinstalls, so a job can pass here and fail there. The image that matches GitHub closely carries a warning in the project's own documentation: "this image is >18GB".
- 266 open issues and 114 open pull requests, and no release since 1 June 2026 even though code landed on 9 August 2026. A fix you need may exist only in unreleased code.
- Its MIT licence file reads only
Copyright (c) 2019. No person and no company is named as the holder.
- dagger/dagger
Runs build pipelines in containers on any machine or service, so it is portable rather than GitHub-shaped; much larger to learn.
Track this in Scout - firecow/gitlab-ci-local
The same idea for GitLab's pipeline files instead of GitHub's.
Track this in Scout - earthly/earthly
A build tool with repeatable containerised steps; its own README now states that it is no longer actively maintained, and no code has landed since 23 October 2025.
Track this in Scout
# Prerequisite: Docker installed and running. # Linux or macOS, prebuilt: curl --proto '=https' --tlsv1.2 -sSf https://raw.githubusercontent.com/nektos/act/master/install.sh | sudo bash # Or, with the Go toolchain version 1.20 or newer: go install github.com/nektos/act@latest # Then, inside a project that already has a .github/workflows folder: act -l act
