head to head · open source
fastapi vs just-api
fastapi has 102,402 GitHub stars, 9,903 forks, 78 open issues and last shipped 4 days ago. just-api has 814 stars, 36 forks, 19 open issues and last shipped 7 months ago. fastapi leads on adoption by 12,480% (102,402 vs 814 stars). fastapi is written in Python under MIT; just-api is written in JavaScript under MIT. fastapi has attracted 10% as many forks as stars, just-api 4%. fastapi was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (api), 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 | just-api | |
|---|---|---|
| GitHub stars | ★ 102K | ★ 814 |
| License | MIT | MIT |
| Written in | Python | JavaScript |
| Last push | 2026-09-14 | 2026-02-12 |
| Forks | ⑂ 9.9K | ⑂ 36 |
| 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 just-api if
- You want the just-api feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches JavaScript
- You evaluated both and just-api 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 just-api
Just API is a declarative, specification based test framework for REST and GraphQL APIs, written in JavaScript and distributed under the MIT license. It lives in the Node.js ecosystem and runs from the npm package just api . Instead of writing test code, a user describes a request and the response validation rules in a YAML file, and the framework builds the request, sends it to the server, and checks the response against that specification. Each suite can contain one or more specs, and suites run in serial or parallel mode.
read the full just-api overview →
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Frequently asked questions
Is fastapi or just-api more popular?
fastapi has 102,402 GitHub stars and just-api has 814. fastapi has the larger community by that measure.
Are fastapi and just-api free?
Both are open source. fastapi is licensed under MIT and just-api under MIT. Neither carries a licence fee.
What is the difference between fastapi and just-api?
fastapi is written in Python and just-api in JavaScript. 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 just-api?
Choose fastapi if you want the larger community (102,402 stars) or its MIT licence terms. Choose just-api if its feature set, stack or MIT licence fits better. Both are self-hostable.