head to head · open source
faiss vs PageIndex
faiss has 41,251 GitHub stars, 4,584 forks, 327 open issues and last shipped 2 days ago. PageIndex has 39,958 stars, 3,438 forks, 103 open issues and last shipped yesterday. faiss leads on adoption by 3% (41,251 vs 39,958 stars). faiss is written in C++ under MIT; PageIndex is written in Python under MIT. faiss has attracted 11% as many forks as stars, PageIndex 9%. PageIndex 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
| faiss | PageIndex | |
|---|---|---|
| GitHub stars | ★ 41K | ★ 40K |
| License | MIT | MIT |
| Written in | C++ | Python |
| Last push | 2026-11-01 | 2026-11-02 |
| Forks | ⑂ 4.6K | ⑂ 3.4K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick faiss if
- You weight community size — 41K stars and counting
- You want the MIT license terms
- Your stack matches C++
- You value the larger contributor base for long-term maintenance
pick PageIndex if
- You want the PageIndex feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches Python
- You evaluated both and PageIndex fits your workflow better
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 →
About PageIndex
PageIndex: Vectorless, Reasoning based RAG Reasoning based RAG ◦ No Vector DB, No Chunking ◦ Context Aware Retrieval ◦ Reads Like a Human 🌐 Website • ☁️ Cloud • 📖 Docs • 📝 Blog • ✉️ Contact Updates [Aug '26] 🔥 PageIndex SDK : pip install U pageindex now ships local mode : index, retrieve, and chat entirely on your machine with your own LLM key, or point the same client at PageIndex Cloud with an API key. [Aug '26] ⚡ PageIndex Flash : fast tree index generation for text based PDFs, now the default indexing method in PageIndex SDK local mode. Scale PageIndex to Millions of Documents: PageIndex File System is a…
read the full PageIndex overview →
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Frequently asked questions
Is faiss or PageIndex more popular?
faiss has 41,251 GitHub stars and PageIndex has 39,958. faiss has the larger community by that measure.
Are faiss and PageIndex free?
Both are open source. faiss is licensed under MIT and PageIndex under MIT. Neither carries a licence fee.
What is the difference between faiss and PageIndex?
faiss is written in C++ and PageIndex in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, faiss or PageIndex?
Choose faiss if you want the larger community (41,251 stars) or its MIT licence terms. Choose PageIndex if its feature set, stack or MIT licence fits better. Both are self-hostable.