Drupal is a free and open source content management system (CMS) that can be used to build various types of websites and applications. External Services at the European Bioinformatics Institute uses Drupal to manage 33 portals, 23 EU project sites, and 10 internal EBI sites. Drupal provides tools for content authors to create, edit, and manage content through a web interface, and also gives developers flexibility to customize sites through modules, themes, and code. ES supports use of Drupal through virtual machines, version control, and development resources.