Yioop! is a PHP search engine. Yioop! can be configured as either a general purpose search engine for the whole Web or it can be configured to provide search results for a set of URLs or domains. Yioop can crawl pages or can directly index archives such as ARC and WARC. It supports indexing several file formats such as HTML, Atom, PDF, DOC, PPT, RTF, RSS, XML, SVG, PNG, JPG, BMP, GIF, and sitemaps. The Yioop! crawler can be deployed on one or many machines. It supports having one or more to crawl scheduler processes, as well as multiple fetchers and mirrors. Crawling respects robots.txt including Crawl-delay. Yioop! crawls are stored in a Web archive format that is easy to move around. Crawling can be done on one machine and the results deployed elsewhere. Yioop! supports mixing of crawls. Yioop! comes with a search front end that can be localized as desired using a GUI. This GUI supports RTL languages. Management of crawls can also be done using this GUI. Yioop! can be configured in a straightforward manner to make use of file caching or memcache if available.