eZ Publish is an open source content management system (CMS) and a development framework (CMF). While the CMS is standardized out of the box functionality and solutions of eZ Publish, the CMF consists of flexible engines for further customization and extensions. The CMS and CMF are seamlessly integrated and part of the eZ Publish distribution. Based on the same software, eZ Publish has two versions; the eZ Publish Pro (a commercial non-GPL version) and eZ Publish GPL (free open source GPL license version).