head to head · open source
fastapi vs Scalar
fastapi has 102,402 GitHub stars, 9,903 forks, 78 open issues and last shipped 4 days ago. Scalar has 16,136 stars, 937 forks, 68 open issues and last shipped yesterday. fastapi leads on adoption by 535% (102,402 vs 16,136 stars). fastapi is written in Python under MIT; Scalar is written in TypeScript under MIT. fastapi has attracted 10% as many forks as stars, Scalar 6%. Scalar was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 3 topic tags (api, 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 | Scalar | |
|---|---|---|
| GitHub stars | ★ 102K | ★ 16K |
| License | MIT | MIT |
| Written in | Python | TypeScript |
| Last push | 2026-09-14 | 2026-09-17 |
| Forks | ⑂ 9.9K | ⑂ 937 |
| 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 Scalar if
- You want the Scalar feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches TypeScript
- You evaluated both and Scalar 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 Scalar
Scalar is open source API documentation and testing platform. It lives in TypeScript ecosystem, with Vue in topics, and targets REST API, OpenAPI, Swagger, API client, docs, http client, reference work. License is MIT. It gives interactive API reference from OpenAPI/Swagger documents, plus built in API testing tool. It also gives offline first API client built for OpenAPI.
read the full Scalar overview →
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Frequently asked questions
Is fastapi or Scalar more popular?
fastapi has 102,402 GitHub stars and Scalar has 16,136. fastapi has the larger community by that measure.
Are fastapi and Scalar free?
Both are open source. fastapi is licensed under MIT and Scalar under MIT. Neither carries a licence fee.
What is the difference between fastapi and Scalar?
fastapi is written in Python and Scalar in TypeScript. 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 Scalar?
Choose fastapi if you want the larger community (102,402 stars) or its MIT licence terms. Choose Scalar if its feature set, stack or MIT licence fits better. Both are self-hostable.