OpenSearch is a collection of technologies that allow the publishing of search results in a format suitable for syndication and aggregation. Introduced in 2005, it is a way for websites and search engines to publish search results in a standard and accessible format. OpenSearch was developed by Amazon.com subsidiary A9 and the first version, OpenSearch 1.0, was unveiled by Jeff Bezos at the O'Reilly Emerging Technology Conference on 15 March 2005. Draft versions of OpenSearch 1.1 were released during September and December 2005. The OpenSearch specification is licensed by A9 under the Creative Commons Attribution-ShareAlike 2.5 License.

Support

Web browsers that support OpenSearch include Safari, Microsoft Edge, Firefox and Google Chrome. Mozilla have indicated that they will deprecate OpenSearch search addons in favour of WebExtensions search addons. This will not affect the ability to manually add an OpenSearch engine from a website As of December 5, 2019, search engine add-ons for Firefox that are powered by OpenSearch have been removed from Mozilla Add-ons.

Design

OpenSearch consists of: OpenSearch Description Documents list search result responses for the given website/tool. Version 1.0 of the specification only allowed one response, in RSS format; however, version 1.1 provides support for multiple responses, which may be in any format. RSS and Atom are the only ones formally supported by OpenSearch aggregators, however other types, such as HTML are perfectly acceptable.

Alternatives

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