Yacy - Create Your Own Peer-to-Peer Search Engine Network
Yacy is a groundbreaking software that lets you create and manage your own search engine network. It uses a decentralized peer-to-peer network of computers to provide more privacy-friendly results and to distribute the work load of indexing web pages.
Michael Christen, YaCy's author, says it can be used to create an intranet search appliance or as a drop-in replacement for commercial enterprise search systems. It supports a variety of operating systems including Windows, macOS and Linux and can even run on low-energy devices like the Raspberry Pi.
YaCy is based on an open source code base and is free for anyone to use. It requires a computer running at least a 64-bit operating system with a modern CPU and at least 2 GB of memory. The YaCy search page is accessible at localhost:8090 and is easy to customize using a web-based admin interface.
When you run a search query, your local YaCy will exchange index information with other installations over the built-in network protocol or it will search web pages in a private mode. The latter is more complex than the former because it doesn't rely on any central server to assemble and sort results: instead each local YaCy will assemble its own index from a queue of locally cached pages and from indexed pages it received from remote peers and then rank these pages according to a proprietary algorithm. YaCy has several safeguards to protect users' privacy, for example, it skips pages fetched with POST or GET parameters and those requiring HTTP password authorization.