head to head · open source
vllm vs faiss
vllm has 96,158 GitHub stars, 24,317 forks, 7,953 open issues and last shipped yesterday. faiss has 41,251 stars, 4,584 forks, 327 open issues and last shipped 2 days ago. vllm leads on adoption by 133% (96,158 vs 41,251 stars). vllm is written in Python under Apache-2.0; faiss is written in C++ under MIT. vllm has attracted 25% as many forks as stars, faiss 11%. vllm 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
| vllm | faiss | |
|---|---|---|
| GitHub stars | ★ 96K | ★ 41K |
| License | Apache-2.0 | MIT |
| Written in | Python | C++ |
| Last push | 2026-11-02 | 2026-11-01 |
| Forks | ⑂ 24K | ⑂ 4.6K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick vllm if
- You weight community size — 96K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick faiss if
- You want the faiss feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches C++
- You evaluated both and faiss fits your workflow better
About vllm
Easy, fast, and cheap LLM serving for everyone 🔥 We have built a vLLM website to help you get started with vLLM. Please visit vllm.ai to learn more. For events, please visit vllm.ai/events to join us. About vLLM is a fast and easy to use library for LLM inference and serving. Originally developed in the Sky Computing Lab at UC Berkeley, vLLM has grown into one of the most active open source AI projects built and maintained by a diverse community of many dozens of academic institutions and companies from over 2000 contributors. vLLM is fast with: State of the art serving throughput Efficient management of…
About faiss
Faiss Faiss is a library for efficient similarity search and clustering of dense vectors. It contains algorithms that search in sets of vectors of any size, up to ones that possibly do not fit in RAM. It also contains supporting code for evaluation and parameter tuning. Faiss is written in C++ with complete wrappers for Python/numpy. Some of the most useful algorithms are implemented on the GPU. It is developed primarily at Meta's Fundamental AI Research group. News See CHANGELOG.md for detailed information about latest features. Introduction Faiss contains several methods for similarity search. It assumes that…
read the full faiss overview →
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Frequently asked questions
Is vllm or faiss more popular?
vllm has 96,158 GitHub stars and faiss has 41,251. vllm has the larger community by that measure.
Are vllm and faiss free?
Both are open source. vllm is licensed under Apache-2.0 and faiss under MIT. Neither carries a licence fee.
What is the difference between vllm and faiss?
vllm is written in Python and faiss in C++. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, vllm or faiss?
Choose vllm if you want the larger community (96,158 stars) or its Apache-2.0 licence terms. Choose faiss if its feature set, stack or MIT licence fits better. Both are self-hostable.