head to head · open source
faiss vs cognee
faiss has 41,251 GitHub stars, 4,584 forks, 327 open issues and last shipped 2 days ago. cognee has 33,012 stars, 3,448 forks, 495 open issues and last shipped yesterday. faiss leads on adoption by 25% (41,251 vs 33,012 stars). faiss is written in C++ under MIT; cognee is written in Python under Apache-2.0. faiss has attracted 11% as many forks as stars, cognee 10%. cognee 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 | cognee | |
|---|---|---|
| GitHub stars | ★ 41K | ★ 33K |
| License | MIT | Apache-2.0 |
| 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 cognee if
- You want the cognee feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Python
- You evaluated both and cognee 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…
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About cognee
Cognee The Open Source AI Memory Platform for Agents Demo . Docs . Learn More · Join Discord · Join r/AIMemory . Community Plugins & Add ons Cognee is the open source AI memory platform that gives AI agents persistent long term memory across sessions. Ingest data in any format, build a self hosted knowledge graph, and let every agent recall, connect, and act with full context 🌐 This README is also available in: Deutsch Español Français 日本語 한국어 Português Русский 中文 📄 Read the research paper: Optimizing the Interface Between Knowledge Graphs and LLMs for Complex Reasoning — Markovic et al., 2025 When to use…
read the full cognee overview →
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Frequently asked questions
Is faiss or cognee more popular?
faiss has 41,251 GitHub stars and cognee has 33,012. faiss has the larger community by that measure.
Are faiss and cognee free?
Both are open source. faiss is licensed under MIT and cognee under Apache-2.0. Neither carries a licence fee.
What is the difference between faiss and cognee?
faiss is written in C++ and cognee 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 cognee?
Choose faiss if you want the larger community (41,251 stars) or its MIT licence terms. Choose cognee if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.