head to head · open source
fastapi vs swagger-core
fastapi has 102,402 GitHub stars, 9,903 forks, 78 open issues and last shipped 4 days ago. swagger-core has 7,530 stars, 2,259 forks, 197 open issues and last shipped yesterday. fastapi leads on adoption by 1,260% (102,402 vs 7,530 stars). fastapi is written in Python under MIT; swagger-core is written in Java under Apache-2.0. fastapi has attracted 10% as many forks as stars, swagger-core 30%. swagger-core was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (openapi, openapi3), 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 | swagger-core | |
|---|---|---|
| GitHub stars | ★ 102K | ★ 7.5K |
| License | MIT | Apache-2.0 |
| Written in | Python | Java |
| Last push | 2026-09-14 | 2026-09-17 |
| Forks | ⑂ 9.9K | ⑂ 2.3K |
| 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 swagger-core if
- You want the swagger-core feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Java
- You evaluated both and swagger-core 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 swagger-core
Swagger Core is the Java implementation of the OpenAPI Specification that generates a machine readable REST API description from JAX RS2 annotations and Java classes, intended for Java server developers and API platform teams that publish and maintain OpenAPI documents alongside their services.
read the full swagger-core overview →
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Frequently asked questions
Is fastapi or swagger-core more popular?
fastapi has 102,402 GitHub stars and swagger-core has 7,530. fastapi has the larger community by that measure.
Are fastapi and swagger-core free?
Both are open source. fastapi is licensed under MIT and swagger-core under Apache-2.0. Neither carries a licence fee.
What is the difference between fastapi and swagger-core?
fastapi is written in Python and swagger-core in Java. 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 swagger-core?
Choose fastapi if you want the larger community (102,402 stars) or its MIT licence terms. Choose swagger-core if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.