Sphider – PHP Search Engine

Sphider is a lightweight web spider and search engine written in PHP, using MySQL as its back end database. It is a great tool for adding search functionality to your web site or building your custom search engine. Sphider is small, easy to set up and modify, and is used in thousands of websites across the world.

Sphider is a popular open-source web spider and search engine. It includes an automated crawler, which can follow links found on a site, and an indexer which builds an index of all the search terms found in the pages. It is written in PHP and uses MySQL as its back end database (requires version 4 or above for both).