head to head · open source
fastapi vs connexion
fastapi has 102,409 GitHub stars, 9,906 forks, 78 open issues and last shipped 4 days ago. connexion has 4,612 stars, 784 forks, 186 open issues and last shipped 11 days ago. fastapi leads on adoption by 2,120% (102,409 vs 4,612 stars). fastapi is written in Python under MIT; connexion is written in Python under Apache-2.0. fastapi has attracted 10% as many forks as stars, connexion 17%. fastapi was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (openapi, python), 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 | connexion | |
|---|---|---|
| GitHub stars | ★ 102K | ★ 4.6K |
| License | MIT | Apache-2.0 |
| Written in | Python | Python |
| Last push | 2026-09-14 | 2026-09-07 |
| Forks | ⑂ 9.9K | ⑂ 784 |
| 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 connexion if
- You want the connexion feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Python
- You evaluated both and connexion 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 connexion
Connexion is an Apache 2.0 licensed Python web framework for spec first and API first development that connects an OpenAPI or Swagger specification to Python handler code, built for Python developers and platform teams who want the specification to drive the implementation instead of being generated from it.
read the full connexion overview →
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Frequently asked questions
Is fastapi or connexion more popular?
fastapi has 102,409 GitHub stars and connexion has 4,612. fastapi has the larger community by that measure.
Are fastapi and connexion free?
Both are open source. fastapi is licensed under MIT and connexion under Apache-2.0. Neither carries a licence fee.
What is the difference between fastapi and connexion?
fastapi is written in Python and connexion 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 connexion?
Choose fastapi if you want the larger community (102,409 stars) or its MIT licence terms. Choose connexion if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.