# What is Faiss?

Source: https://zilliz.com/ai-faq/what-is-faiss
Author: zilliz

Faiss (Facebook AI Similarity Search) is an open-source library developed by Meta (formerly Facebook) for efficient similarity search and clustering of dense vectors. It’s widely used in AI applications where fast nearest neighbor searches are essential, such as recommendation systems, image retrieval, and natural language processing.
Faiss is optimized for handling large datasets of vectors, making it a powerful tool for searching millions—or even billions—of high-dimensional data points. It achieves this efficiency through indexing techniques such as hierarchical clustering, product quantization, and approximate nearest neighbor (ANN) search. These methods significantly reduce computational overhead while maintaining high accuracy.
One of Faiss’s standout features is its GPU acceleration, allowing massive datasets to be processed quickly using NVIDIA GPUs. Developers frequently pair Faiss with vector databases like Milvus to manage and search embeddings effectively.