head to head · open source
fastapi vs schemathesis
fastapi has 104,566 GitHub stars, 10,179 forks, 78 open issues and last shipped yesterday. schemathesis has 3,738 stars, 231 forks, 7 open issues and last shipped yesterday. fastapi leads on adoption by 2,697% (104,566 vs 3,738 stars). fastapi is written in Python under MIT; schemathesis is written in Python under MIT. fastapi has attracted 10% as many forks as stars, schemathesis 6%. schemathesis was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (api, openapi), 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.
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Side by side
| fastapi | schemathesis | |
|---|---|---|
| GitHub stars | ★ 105K | ★ 3.7K |
| License | MIT | MIT |
| Written in | Python | Python |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 10K | ⑂ 231 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick fastapi if
- You weight community size — 105K stars and counting
- You want the MIT license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick schemathesis if
- You want the schemathesis feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches Python
- You evaluated both and schemathesis fits your workflow better
About fastapi
FastAPI framework, high performance, easy to learn, fast to code, ready for production Documentation : Source Code : FastAPI is a modern, fast (high performance), web framework for building APIs with Python based on standard Python type hints. The key features are: Fast : Very high performance, on par with NodeJS and Go (thanks to Starlette and Pydantic). One of the fastest Python frameworks available. Fast to code : Increase the speed to develop features by about 200% to 300%. Fewer bugs : Reduce about 40% of human (developer) induced errors. Intuitive : Great editor support. Completion everywhere. Less time…
read the full fastapi overview →
About schemathesis
Schemathesis Catch API bugs before your users do. Schemathesis tests OpenAPI and GraphQL APIs by generating inputs from your schema, adapting to server responses, and chaining operations into realistic workflows. Finding bugs that manual testing missed Try it now What problems does it solve? 💥 500 errors that crash your API on edge case inputs 📋 Schema violations where your API returns different data than documented 🚪 Validation bypasses where invalid data gets accepted 🔗 Integration failures when responses don't match client expectations 🔄 Stateful bugs where operations work individually but fail in…
read the full schemathesis overview →
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Frequently asked questions
Is fastapi or schemathesis more popular?
fastapi has 104,566 GitHub stars and schemathesis has 3,738. fastapi has the larger community by that measure.
Are fastapi and schemathesis free?
Both are open source. fastapi is licensed under MIT and schemathesis under MIT. Neither carries a licence fee.
What is the difference between fastapi and schemathesis?
fastapi is written in Python and schemathesis 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, fastapi or schemathesis?
Choose fastapi if you want the larger community (104,566 stars) or its MIT licence terms. Choose schemathesis if its feature set, stack or MIT licence fits better. Both are self-hostable.