WordPress is a free and open-source content management system based on PHP and MySQL. Features include a plugin architecture and a template system. It is usually associated with blogging and entry-level CMS. In fact WordPress has evolved to a full-featured CMS. Still weak when it comes to fine-grained security of content, it is nevertheless the jack of all trades of the CMS world. More than 5 million websites are based on WordPress and new projects are creating the foundation for WordPress to be one of the leading headless CMS.