head to head · open source
Harness vs pytest-testmon
Harness has 38,384 GitHub stars, 3,398 forks, 106 open issues and last shipped yesterday. pytest-testmon has 1,015 stars, 81 forks, 38 open issues and last shipped 10 months ago. Harness leads on adoption by 3,682% (38,384 vs 1,015 stars). Harness is written in Go under Apache-2.0; pytest-testmon is written in Python under MIT. Harness has attracted 9% as many forks as stars, pytest-testmon 8%. Harness was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (ci), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
← all 8884 open source comparisons
Side by side
| Harness | pytest-testmon | |
|---|---|---|
| GitHub stars | ★ 38K | ★ 1.0K |
| License | Apache-2.0 | MIT |
| Written in | Go | Python |
| Last push | 2026-09-17 | 2025-12-01 |
| Forks | ⑂ 3.4K | ⑂ 81 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Harness if
- You weight community size — 38K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Go
- You value the larger contributor base for long-term maintenance
pick pytest-testmon if
- You want the pytest-testmon feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches Python
- You evaluated both and pytest-testmon fits your workflow better
About Harness
Harness Open Source is an Apache 2.0, Go based developer platform that combines Git source control management, CI/CD pipelines, Gitspaces hosted development environments and artifact registries into one self hostable system for engineering teams that want end to end software delivery without stitching four separate products together.
read the full Harness overview →
About pytest-testmon
This is a pytest plug in which automatically selects and re executes only tests affected by recent changes. How is this possible in dynamic language like Python and how reliable is it? Read here: Determining affected tests Quickstart pip install pytest testmon build the dependency database and save it to .testmondata pytest testmon change some of your code (with test coverage) only run tests affected by recent changes pytest testmon To learn more about different options you can use with testmon, please head to testmon.org Call for opensource projects: try testmon in CI with no effort or risk. We would like to run…
read the full pytest-testmon overview →
More in Developer Tools
Related comparisons
More Build & Deployment projects
Compare either of these against the rest of the Build & Deployment field.
Frequently asked questions
Is Harness or pytest-testmon more popular?
Harness has 38,384 GitHub stars and pytest-testmon has 1,015. Harness has the larger community by that measure.
Are Harness and pytest-testmon free?
Both are open source. Harness is licensed under Apache-2.0 and pytest-testmon under MIT. Neither carries a licence fee.
What is the difference between Harness and pytest-testmon?
Harness is written in Go and pytest-testmon in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Harness or pytest-testmon?
Choose Harness if you want the larger community (38,384 stars) or its Apache-2.0 licence terms. Choose pytest-testmon if its feature set, stack or MIT licence fits better. Both are self-hostable.