Drupal (pronounced /ˈdruːpəl/) is a free and open source^[2] content management system (CMS) written in PHP and distributed under the GNU General Public License.^[3][4] 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, including whitehouse.gov^[5] and data.gov.uk. It is also used for knowledge management and business collaboration.

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 within a flexible and rich permission / privilege system, create and manage menus, RSS-feeds, customize page layout, perform logging, and administer the system. As installed, Drupal provides options to create a classic brochureware website, a single- or multi-user blog, an Internet forum, or a community website providing for user-generated content.

Although Drupal offers a sophisticated programming interface for developers, no programming skills are required for basic website installation and administration.^[6]

Drupal can run on any computing platform that supports both a web server capable of running PHP version 4.3.5+ (including Apache, IIS, Lighttpd, and nginx) and a database (such as MySQL or PostgreSQL) to store content and settings.^[4]

Originally written by Dries Buytaert as a message board, Drupal became an open source project in 2001.^[7] Drupal is an English rendering of the Dutch word “druppel”, which means “drop” (as in “a water droplet”).^[8] The name was taken from the now-defunct Drop.org website, whose code slowly evolved into Drupal. Buytaert wanted to call the site “dorp” (Dutch for “village”) for its community aspects, but made a typo when checking the domain name and thought it sounded better.^[7]

A large community now helps develop Drupal^[9], and Drupal's popularity is growing rapidly. From May 2007 to April 2008, Drupal was downloaded from the Drupal.org website more than 1.4 million times, an increase of approximately 125% from the previous year.^[10][11]

As of April 2009, over 70 well-known brand names and not-for-profit organizations use Drupal.^[12] Drupal has also won several Packt Open Source CMS Awards^[13] and three times (in a row) won the Webware 100.^[14][15]

Drupal 6.15, released in December 2009, is the latest release.^[16] On March 5, 2009, Dries Buytaert announced a code freeze for Drupal 7 for September 1, 2009.^[17] The latest test version, DRUPAL-7-0-ALPHA-2, was released on February 23, 2010.^[18] There is no date announced yet for the final release of Drupal 7.