WordPress is probably the most popular CMS. It is used by over 40% of all websites whose CMS is known, making it the most widely used system to run them. Out of a million of the most visited websites, about a third use WordPress. Extensions can be used to extend websites to meet requirements. (e.g. custom fields, backup functionality, multilingualism, security, etc.) A distinction must be made here between free and paid plugins., TYPO3 is an open source CMS that can be used to create websites, portals, intranets, extranets, etc., Joomla is another very popular CMS. It is an open source system and completely free. However, you will need to sign up for an annual subscription in order to use many of the advanced features., Drupal is another very popular CMS that offers great flexibility and power. It is free and open source., Magento is a complete eCommerce solution. It is easy to install and configure. It has many useful tools like SEO tools, security features, etc., Contao is an open source CMS based on PHP and MySQL. It allows you to create websites without any programming knowledge., Redaxo is an all-in-one solution for web designers, developers, marketers and business owners who want to create websites without having to learn HTML, CSS, PHP or any other programming language.