XWiki is a free wiki software platform written in Java with a design emphasis on extensibility. XWiki is an enterprise wiki. It includes WYSIWYG editing, OpenDocument based document import/export, semantic annotations and tagging, and advanced permissions management.

As an application wiki, XWiki allows for the storing of structured data and the execution of server-side script within the wiki interface. Scripting languages including Velocity, Apache Groovy, Python, Ruby and PHP can be written directly into wiki pages using wiki macros. User-created data structures can be defined in wiki documents and instances of those structures can be attached to wiki documents, stored in a database, and queried using either Hibernate query language or XWiki's own query language.

XWiki.org's extension wiki is home to XWiki extensions ranging from code snippets which can be pasted into wiki pages to loadable core modules. Many of XWiki Enterprise's features are provided by extensions which are bundled with it.

The wikitext is rendered using the XWiki Rendering Engine which extends WikiModel and Doxia systems, allowing it to parse Confluence, JSPWiki, Creole, MediaWiki, and TWiki syntaxes as well as XWiki's own syntax. XWiki pages are written by default using the WYSIWYG editor and rendered with XWiki syntax to format text, create tables, create links, display images, etc.