OpenSearch is a collection of technologies that allow the publishing of search results in a format suitable for syndication and aggregation.

[4] Web browsers that support OpenSearch include Safari,[5] Microsoft Edge,[6] Firefox[7] and Google Chrome.

This will not affect the ability to manually add an OpenSearch engine from a website[9] As of December 5, 2019, search engine add-ons for Firefox that are powered by OpenSearch have been removed from Mozilla Add-ons.

RSS and Atom are the only ones formally supported by OpenSearch aggregators, however other types, such as HTML are perfectly acceptable.

Mozilla Firefox offers a bookmark keyword feature[14] where an occurrence of %s in the bookmark URI gets replaced with the terms typed in the address bar following the initial keyword.