YaCy is a free search engine, decentralized and self-hostable, that makes web search independent of centralized major players. It can operate in two modes: a peer-to-peer (P2P) mode, where your instance joins a global network of shared indexes, and an autonomous mode, where you only index the scope of your choice.

Its principle guarantees the absence of tracking: no user profiling, no centralized censorship, and no advertising. The built-in crawler is configurable (depth, scope, filters) and allows indexing both public sites and intranets or document bases, making it an excellent enterprise search engine.

YaCy exposes a search API, result feeds, and a search box that can be integrated into your own sites, with faceted search and advanced operators. Self-hosted with DINAO, it keeps indexes, queries, and configuration strictly within French territory.