What is the name of the software that powers Wikipedia?

The software that powers Wikipedia is MediaWiki. It is a free, open-source wiki platform developed for the Wikimedia projects and maintained by the Wikimedia Foundation.

Wikipedia did not begin with MediaWiki. When the site launched in January 2001, it used UseModWiki, a Perl-based system that stored pages in text files. As Wikipedia grew, Magnus Manske developed a PHP-based replacement, introduced in January 2002. Further improvements by Lee Daniel Crocker produced the software that was later named MediaWiki in 2003.

MediaWiki stores article text, revision histories, links, user accounts, and other information in databases. Its architecture includes caching, database replication, extensions, templates, and specialized tools needed to handle Wikipedia's enormous traffic and editing history.

A common mix-up is confusing MediaWiki with Wikimedia or Wikipedia. Wikipedia is the encyclopedia, Wikimedia is the foundation and family of projects, and MediaWiki is the software platform. MediaWiki also powers Wiktionary, Wikimedia Commons, Wikidata, and many independent wikis.