head to head · open source
fastapi vs arex-agent-java
fastapi has 104,566 GitHub stars, 10,179 forks, 78 open issues and last shipped yesterday. arex-agent-java has 572 stars, 143 forks, 74 open issues and last shipped 2 months ago. fastapi leads on adoption by 18,181% (104,566 vs 572 stars). fastapi is written in Python under MIT; arex-agent-java is written in Java under Apache-2.0. fastapi has attracted 10% as many forks as stars, arex-agent-java 25%. fastapi was the more recently maintained of the two, and both are self-hostable with no licence fee.
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 | arex-agent-java | |
|---|---|---|
| GitHub stars | ★ 105K | ★ 572 |
| License | MIT | Apache-2.0 |
| Written in | Python | Java |
| Last push | 2026-11-02 | 2026-09-02 |
| Forks | ⑂ 10K | ⑂ 143 |
| 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 arex-agent-java if
- You want the arex-agent-java 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 arex-agent-java 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 arex-agent-java
AREX An Open Source Testing Framework with Real World Data Introduction Building Getting Started Contributing License Introduction As your application evolves more complex, the effort required to thoroughly test against it also becomes tremendous. Arex is a framework designed around a quite straightforward principle of leveraging your real world data(i.e. database record, service payload, cache items etc.) for regression testing. Simple is powerful. The idea behind makes it incredibly powerful. AREX provides an out of box agent file that could be attached to any applications with Java 8+ and dynamically weaves…
read the full arex-agent-java overview →
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Frequently asked questions
Is fastapi or arex-agent-java more popular?
fastapi has 104,566 GitHub stars and arex-agent-java has 572. fastapi has the larger community by that measure.
Are fastapi and arex-agent-java free?
Both are open source. fastapi is licensed under MIT and arex-agent-java under Apache-2.0. Neither carries a licence fee.
What is the difference between fastapi and arex-agent-java?
fastapi is written in Python and arex-agent-java 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 arex-agent-java?
Choose fastapi if you want the larger community (104,566 stars) or its MIT licence terms. Choose arex-agent-java if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.