head to head · open source
fastapi vs Scalar
fastapi has 104,566 GitHub stars, 10,179 forks, 78 open issues and last shipped yesterday. Scalar has 16,364 stars, 964 forks, 75 open issues and last shipped yesterday. fastapi leads on adoption by 539% (104,566 vs 16,364 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 | ★ 105K | ★ 16K |
| License | MIT | MIT |
| Written in | Python | TypeScript |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 10K | ⑂ 964 |
| 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 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 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 Scalar
Scalar Interactive API Reference from OpenAPI/Swagger └ Renders OpenAPI/Swagger documents └ Comes with an API testing tool └ Doesn't look like 2011 └ Generates code examples for many languages & frameworks └ Integrates with your favorite framework └ Try Demo An offline first API Client built for OpenAPI └ Free and open source └ First class OpenAPI/Swagger support └ Integrates with dozens of API Frameworks (Elysia, Hono, FastAPI, etc) └ Syncs with your favorite server framework (Watch Mode) └ Has environment variables, dynamic parameters and everything └ Try It in the Browser └ Download (Windows, MacOS, Linux)…
read the full Scalar overview →
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Frequently asked questions
Is fastapi or Scalar more popular?
fastapi has 104,566 GitHub stars and Scalar has 16,364. 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 (104,566 stars) or its MIT licence terms. Choose Scalar if its feature set, stack or MIT licence fits better. Both are self-hostable.