head to head · open source
fastapi vs schemathesis
fastapi has 102,402 GitHub stars, 9,903 forks, 78 open issues and last shipped 4 days ago. schemathesis has 3,608 stars, 224 forks, 7 open issues and last shipped yesterday. fastapi leads on adoption by 2,738% (102,402 vs 3,608 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 | ★ 102K | ★ 3.6K |
| License | MIT | MIT |
| Written in | Python | Python |
| Last push | 2026-09-14 | 2026-09-17 |
| Forks | ⑂ 9.9K | ⑂ 224 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick fastapi if
- You weight community size — 102K 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 is an MIT licensed, high performance Python web framework for building APIs with standard Python type hints, aimed at Python developers and teams that need production ready HTTP services with automatic OpenAPI documentation.
read the full fastapi overview →
About schemathesis
Schemathesis is a Python API testing tool that generates test inputs from OpenAPI and GraphQL schemas. It adapts to server responses, chains operations into realistic workflows, and checks whether the API behaves as documented. The project lives in the Python developer tools ecosystem and connects with pytest, unittest, and property based testing workflows.
read the full schemathesis overview →
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Frequently asked questions
Is fastapi or schemathesis more popular?
fastapi has 102,402 GitHub stars and schemathesis has 3,608. 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 (102,402 stars) or its MIT licence terms. Choose schemathesis if its feature set, stack or MIT licence fits better. Both are self-hostable.