head to head · open source
faiss vs Chroma
faiss has 40,939 GitHub stars, 4,527 forks, 327 open issues and last shipped yesterday. Chroma has 29,333 stars, 2,522 forks, 843 open issues and last shipped 2 days ago. faiss leads on adoption by 40% (40,939 vs 29,333 stars). faiss is written in C++ under MIT; Chroma is written in Rust under Apache-2.0. faiss has attracted 11% as many forks as stars, Chroma 9%. 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 | Chroma | |
|---|---|---|
| GitHub stars | ★ 41K | ★ 29K |
| License | MIT | Apache-2.0 |
| Written in | C++ | Rust |
| Last push | 2026-09-19 | 2026-09-18 |
| Forks | ⑂ 4.5K | ⑂ 2.5K |
| 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 Chroma if
- You want the Chroma feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Rust
- You evaluated both and Chroma 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 Chroma
Chroma is an open source vector database designed to store, index, and retrieve embeddings for AI applications. It runs as a local Python or JavaScript client or in client server mode, providing a lightweight infrastructure layer for AI search and retrieval workloads. Built in Rust and licensed under Apache 2.0, it targets developers building RAG, agents, and other embedding dependent systems.
read the full Chroma overview →
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Frequently asked questions
Is faiss or Chroma more popular?
faiss has 40,939 GitHub stars and Chroma has 29,333. faiss has the larger community by that measure.
Are faiss and Chroma free?
Both are open source. faiss is licensed under MIT and Chroma under Apache-2.0. Neither carries a licence fee.
What is the difference between faiss and Chroma?
faiss is written in C++ and Chroma in Rust. 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 Chroma?
Choose faiss if you want the larger community (40,939 stars) or its MIT licence terms. Choose Chroma if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.