head to head · open source
faiss vs Helicone
faiss has 41,256 GitHub stars, 4,586 forks, 327 open issues and last shipped 2 days ago. Helicone has 6,259 stars, 702 forks, 156 open issues and last shipped 8 days ago. faiss leads on adoption by 559% (41,256 vs 6,259 stars). faiss is written in C++ under MIT; Helicone is written in TypeScript under Apache-2.0. faiss has attracted 11% as many forks as stars, Helicone 11%. 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 | Helicone | |
|---|---|---|
| GitHub stars | ★ 41K | ★ 6.3K |
| License | MIT | Apache-2.0 |
| Written in | C++ | TypeScript |
| Last push | 2026-11-03 | 2026-10-28 |
| Forks | ⑂ 4.6K | ⑂ 702 |
| 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 Helicone if
- You want the Helicone feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches TypeScript
- You evaluated both and Helicone 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 Helicone
Docs • Changelog • Bug reports • See Helicone in Action! (Free) Helicone is an AI Gateway & LLM Observability Platform for AI Engineers 🌐 AI Gateway : Access 100+ AI models with 1 API key through the OpenAI API with intelligent routing and automatic fallbacks. Get started in 2 minutes. 🔌 Quick integration : One line of code to log all your requests from OpenAI, Anthropic, LangChain, Gemini, Vercel AI SDK, and more. 📊 Observe : Inspect and debug traces & sessions for agents, chatbots, document processing pipelines, and more 📈 Analyze : Track metrics like cost, latency, quality, and more. Export to PostHog in…
read the full Helicone overview →
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Frequently asked questions
Is faiss or Helicone more popular?
faiss has 41,256 GitHub stars and Helicone has 6,259. faiss has the larger community by that measure.
Are faiss and Helicone free?
Both are open source. faiss is licensed under MIT and Helicone under Apache-2.0. Neither carries a licence fee.
What is the difference between faiss and Helicone?
faiss is written in C++ and Helicone in TypeScript. 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 Helicone?
Choose faiss if you want the larger community (41,256 stars) or its MIT licence terms. Choose Helicone if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.