Faiss

Meta's open-source library for fast similarity search over vectors held in memory, on CPU or GPU.

Ask your AI about this, with this page as the source:ChatGPT ↗Claude ↗Perplexity ↗

Where it fits

Vector Database · Embedded / local-firstA fast in-memory vector index library for research, batch jobs and apps that load their index at startup.Trade-off: A library, not a database — no metadata filtering service, persistence or updates beyond what you build.

Who uses it

No maker's live product on record yet, and 51 open-source projects that declare it in their code.

Declared in code 51How evidence is collected →

We haven't found a maker's live product that uses Faiss yet — only the open-source projects below, which declare it in their code.

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Aix-DB Aix-DB 基于 LangChain/LangGraph 框架，结合 MCP Skills 多智能体协作架构，实现自然语言到数据洞察的端到端转换。Vector DatabaseIn its code · source ↗

awesome-llm-apps 100+ AI Agents, Agent Skills and RAG Apps - Free and Open Source.Vector DatabaseIn its code · source ↗

camel 🐫 CAMEL: The first and the best multi-agent framework. Finding the Scaling Law of Agent…Vector DatabaseIn its code · source ↗

GenerativeAIExamples Generative AI reference workflows optimized for accelerated infrastructure and microserv…Vector DatabaseIn its code · source ↗

semantica Graph-Native Infrastructure for Context and Accountable AI SystemsVector DatabaseIn its code · source ↗

monitor Real-time monitoring, slowlog analysis, and audit trails for Valkey and RedisVector DatabaseIn its code · source ↗

DAMO-ConvAI DAMO-ConvAI: The official repository which contains the codebase for Alibaba DAMO Conver…Vector DatabaseIn its code · source ↗

AI-Bank-Statement-Document-Automation-By-LLM-And-Personal-Finanical-Analysis-Prediction AI Bank Statement Document Automation By LLM model and Personal Finanical AnalysisVector DatabaseIn its code · source ↗

LightRAG [EMNLP2025] LightRAG: Simple and Fast Retrieval-Augmented GenerationVector DatabaseIn its code · source ↗

AdalFlow AdalFlow: The library to build & auto-optimize LLM applications.Vector DatabaseIn its code · source ↗

app-controller App-Controller: Allow users to manipulate your App with natural languageVector DatabaseIn its code · source ↗

team-of-ai-agents Open-source framework to make AI agents' team collaboration as effective as human collab…Vector DatabaseIn its code · source ↗

cocoindex Incremental engine for long horizon agents 🌟 Star if you like it!Vector DatabaseIn its code · source ↗

Agent-First-Organization The official Python library for Arklex frameworkVector DatabaseIn its code · source ↗

Memori Memori is agent-native memory infrastructure. A LLM-agnostic layer that turns agent exec…Vector DatabaseIn its code · source ↗

trustgraph The Semantic Intelligence Layer for OntologiesVector DatabaseIn its code · source ↗

ez-ai-agent Automated Penetration Testing with EZ and AgentsVector DatabaseIn its code · source ↗

arg 公司知识库助手Vector DatabaseIn its code · source ↗

evolving-agents Your toolkit for autonomous, evolving agent ecosystems. Create, execute, govern, and evo…Vector DatabaseIn its code · source ↗

Langchain-Chatchat Langchain-Chatchat（原Langchain-ChatGLM）基于 Langchain 与 ChatGLM, Qwen 与 Llama 等语言模型的 RAG 与…Vector DatabaseIn its code · source ↗

minions Big & Small LLMs working togetherVector DatabaseIn its code · source ↗

trulens Evaluation and Tracking for LLM Experiments and AI AgentsVector DatabaseIn its code · source ↗

FlowReasoner Vector DatabaseIn its code · source ↗

Open source: a project that declares Faiss as a dependency in its public code — verifiable, but not necessarily a live product.

Reliability and open issues

Most wanted on GitHub

uv pip install support👍 21 · opened Aug 2025 · active Sep 2026

Open on 2026-10-04 in facebookresearch/faiss, with activity in the last year — issues and feature requests by 👍.

Alternatives to Faiss

All alternatives by situation →

pgvectorApps already on Postgres that want vector search in the same database, joined with normal tables.Open sourceFree tier

ChromaPrototyping RAG on your laptop with a pip or npm install and no server to run.Open sourceFree tier13 makers · vector database

PineconeA fully hosted index with nothing to operate, sized by usage.Free tier55 makers · vector database

QdrantHeavy metadata filtering alongside vector search, self-hosted from one binary or on its managed cloud.Open sourceFree tier18 makers · vector database

WeaviateHybrid search that mixes keyword and vector results, with built-in modules that can create embeddings for you.Open sourceFree tier16 makers · vector database

turbopufferVery large or many-tenant indexes where storing everything on object storage keeps cost down.8 makers · vector database

LanceDBAn embedded vector database that stores vectors and data as files on local disk or object storage, with no server to run.Open sourceFree tier3 makers · vector database

MongoDBApps already on MongoDB Atlas that want vector search on the same documents, with no second store to sync.Self-hostableFree tier

Questions makers ask about Faiss

Is Faiss free?

Yes — it is free, open-source software.

Is Faiss open source or self-hostable?

Open source, and you can self-host it. source ↗

Can AI coding agents work with Faiss?

No llms.txt, official MCP server or CLI found yet.

Who uses Faiss?

No maker's live product we track yet; 51 open-source projects declare it in their code. source ↗