head to head · open source
faiss vs txtai
faiss has 40,939 GitHub stars, 4,527 forks, 327 open issues and last shipped yesterday. txtai has 12,964 stars, 891 forks, 9 open issues and last shipped 5 days ago. faiss leads on adoption by 216% (40,939 vs 12,964 stars). faiss is written in C++ under MIT; txtai is written in Python under Apache-2.0. faiss has attracted 11% as many forks as stars, txtai 7%. faiss 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 | txtai | |
|---|---|---|
| GitHub stars | ★ 41K | ★ 13K |
| License | MIT | Apache-2.0 |
| Written in | C++ | Python |
| Last push | 2026-09-19 | 2026-09-15 |
| Forks | ⑂ 4.5K | ⑂ 891 |
| 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 txtai if
- You want the txtai 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 txtai fits your workflow better
About faiss
Faiss is an MIT licensed C++ library for efficient similarity search and clustering of dense vectors, with complete Python and NumPy wrappers, developed primarily at Meta's Fundamental AI Research group, and it is intended for engineers and researchers who need nearest neighbour search over vector sets that range from small collections to sets that possibly do not fit in RAM.
read the full faiss overview →
About txtai
txtai is an all in one AI framework for semantic search, LLM orchestration and language model workflows, written in Python and released under the Apache 2.0 license. It lives in the Python machine learning ecosystem and is built on Hugging Face Transformers, Sentence Transformers and FastAPI. The core component is an embeddings database, which is a union of vector indexes (both sparse and dense), graph networks and relational databases. That foundation enables vector search and also serves as a knowledge source for large language model applications.
read the full txtai overview →
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Frequently asked questions
Is faiss or txtai more popular?
faiss has 40,939 GitHub stars and txtai has 12,964. faiss has the larger community by that measure.
Are faiss and txtai free?
Both are open source. faiss is licensed under MIT and txtai under Apache-2.0. Neither carries a licence fee.
What is the difference between faiss and txtai?
faiss is written in C++ and txtai 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 txtai?
Choose faiss if you want the larger community (40,939 stars) or its MIT licence terms. Choose txtai if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.