TYPO3 is a free and open source web content management system written in PHP. It is released under the GNU General Public License. It can run on several web servers, such as Apache or IIS, on top of many operating systems, among them Linux, Microsoft Windows, FreeBSD, Mac OS X and OS/2.TYPO3 is, along with Drupal, Joomla! and WordPress, among the most popular content management systems worldwide, however it is more widespread in Europe than in other regions.