Drupal is an open source modular framework and Content Management System (CMS) written in PHP. It is used as a "back end" system for many different types of websites, ranging from small personal blogs to large corporate and political sites.

The standard release of Drupal, known as "Drupal core", contains basic features common to most CMSs. These include the ability to register and maintain individual user accounts, administration menus, RSS-feeds, customizable layout, flexible account privileges, logging, a blogging system, an Internet forum, and options to create a classic "brochureware" website or an interactive community website.