Most popular Open Source CMS are :
WordPress has been used mainly as a blogging platform, but nowadays with this CMS can be used not only for fully functional website development, but also for the creation of mobile applications
Joomla as well as most website development CMS is a open source platform. Joomla is PHP-based and uses MySQL database to store content. With the help of Joomla you or your web developers will be able to make your preferred website development project.
Magento is a CMS that is extremely easy to use and will facilitate the work with servicing of clients, which is a very important criteria for today’s eCommerce websites. In case you were wondering whether to use Magento for your website development project, keep in mind that it is vital your site be mobile-optimised.
Drupal is an extremely flexible website development CMS and can be tailored to the needs of every business. However, it isn’t as user-friendly as WordPress or Joomla, due to the fact that it is a new website development CMS and is a heavier platform compared to the above CMSs, and so is not the preferred choice by the majority.