act vs Earthly
A side-by-side comparison of two self-hosted ci/cd & build options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | act | Earthly |
|---|---|---|
| Deploy effort | Read-the-docs project | Under-an-hour setup |
| Health score | 98 · Excellent | 54 · Fair |
| Category | CI/CD & Build | CI/CD & Build |
| License | MIT | MPL-2.0 |
| Language | Go | Go |
| Setup difficulty | Easy | Medium |
| Min. RAM | 256 MB | 512 MB |
| Deployment | bare-metal, binary | binary, docker |
| GitHub stars | ★ 72,082 | ★ 12,048 |
| First released | 2019 | 2020 |
| Replaces | GitHub Actions | Make, GitHub Actions |
What are act and Earthly?
act
act lets developers run GitHub Actions workflows on their own machine using Docker, providing fast local feedback before pushing. It reads the same workflow files used by GitHub so behavior closely matches CI.
- Local GitHub Actions runs
- Docker-based execution
- Reuses workflow files
- Fast feedback loop
Earthly
Earthly is an open-source build automation tool that runs reproducible builds inside containers using a syntax that combines Dockerfiles and Makefiles. It works the same on any CI system or locally.
- Reproducible container builds
- Works on any CI
- Parallel build execution
- Build cache support
act vs Earthly: key differences
Both projects are written in Go. Licensing differs — MIT for act versus MPL-2.0 for Earthly. Act is the lighter option, starting around 256 MB of RAM against 512 MB for Earthly. Act has the considerably larger community, at 72,082 GitHub stars versus 12,048. Earthly lists first-class Docker deployment; act does not.
Why pick each one
Choose act if…
- Test CI before pushing
- Saves CI minutes
Watch out for
- Not all actions supported
- Docker required
Choose Earthly if…
- Released under the MPL-2.0 license
- First-class Docker support for quick deployment
- Mature project with 12k GitHub stars
- Written in Go
Frequently asked questions
Is act or Earthly better?
act is the stronger all-round pick: it has both the larger community and the simpler easy setup. Consider Earthly if its specific feature set fits your needs better.
Are act and Earthly free and open-source?
Yes. act is licensed under MIT and Earthly under MPL-2.0. Both can be self-hosted at no software cost.
Can I run act and Earthly with Docker?
act: check the project docs for container support. Earthly: yes.
Which is lighter on resources, act or Earthly?
act has the smaller minimum footprint at 256 MB of RAM, compared to about 512 MB for Earthly. Real-world usage depends on library size, user count, and enabled features.