Open Source Content Management Software
Mixcore CMS
Mixcore CMS is an Open Source Enterprise ASP.NET Core / Dotnet Core CMS for building amazing digital experiences. It's made by a dedicated community. Anyone can use it, and it will always be free.
Flextype
Flextype is super fast headless content management system with an elegant architecture and built-in smart cache.
CouchCMS
With no knowledge of PHP required at all you can make any static web-page editable by your clients.
CppCMS
CppCMS is a free and open-source, high performance web development framework. CppCMS is not a content management system but rather a C++ web framework that has been designed for rapid web application development. Applications built with CppCMS are capable high loads with high request throughput.
TourCMS
TourCMS is a web based reservation system for tour operators and travel agencies, TourCMS - Tour operator reservation system and website CMS
TYPO3
TYPO3 is a free and open-source content management system written in PHP. The CMS is released under the GNU General Public License which makes it free to use for commerical and non-commercial projects alike. TYPO3 can run in most hosting environements and provides an easy way for people to write, manage and publish content online.
Plone CMS
Plone CMS is a free and open source content management system written in Python. The CMS is built on top of the Zope application server, a free and open source web application server written in the object-oriented programming language Python. The significant strength of Plone is its flexibility, allowing users to manage the lifecycle of their workflow, from creation to publication and storage, with version control, content locking, and digital asset and document management. Plone has an active, thriving open source community that holds annual conferences, regional symposia, and many sprints all over the world. Which means that anyone if free to join and improve the codebase
DatoCMS
Connect DatoCMS to your favorite site generator, build the perfect backend and deploy anywhere you like.
SilverStripe
Silverstripe CMS is designed to be simple to learn and easy to use. Whether updating a page or publishing multiple pages on a large scale site. Give access to edit only specific areas of your site. Architected to safeguard your data from malicious activity or data-loss, even while scaling up complex sites.