YaCy

YaCy (pronounced "ya see") is a free distributed search engine, built on principles of peer-to-peer (P2P) networks. Its core is a computer program written in Java distributed on several hundred computers, , so-called YaCy-peers. Each YaCy-peer independently crawls through the Internet, analyzes and indexes found web pages, and stores indexing results in a common database (so called index) which is shared with other YaCy-peers using principles of P2P networks. It is a search engine that everyone can use to build a search portal for their intranet and to help search the public internet clearly.
Compared to semi-distributed search engines, the YaCy-network has a decentralised architecture. All YaCy-peers are equal and no central server exists. It can be run either in a crawling mode or as a local proxy server, indexing web pages visited by the person running YaCy on their computer. (Several mechanisms are provided to protect the user's privacy). Access to the search functions is made by a locally running web server which provides a search box to enter search terms, and returns search results in a similar format to other popular search engines.
YaCy was created in 2003 by Michael Christen.
System components.
YaCy search engine is based on four elements:
YaCy platform architecture.
YaCy uses a combination of techniques for the networking, administration, and maintenance of indexing the search engine including blacklisting, moderation, and communication with the community. Here is how YaCy performs these operations:
Distribution.
YaCy is available on Windows, Mac, Linux and other platforms via Docker
The Debian package can be installed from a repository available at the subdomain of the project's website. The package is not maintained in the official Debian package repository yet.
Further reading.
YaCy at LinuxReviews