SilverStripe

vs

Progress Sitefinity

Joomla is a free and open-source content management system written in PHP. The CMS is built entirely by volunteers from all over the world and has a strong community that provide educational resources, and extensions. 

Django CMS is a free and open-source content management system build on the Python web framework Django. With Django CMS, you can create your own website or blog in a matter of minutes which is easy to maintain far into the future. If you are a developer utilizing the Django framework you can integrate Django CMS into an exiting Django application and take advantage of it's publishing and editing features.

CMS Made Simple is a free and open-source content management system that offers an easy to use interface for end users, while maintaining a powerful backend for developers. CMS Made Simple is written in PHP and got an extensive API and custom modules. The CMS also utilize the Smarty templating engine that can be used to customize sites with HTML, CSS and PHP.

The Mura CMS platform makes it easier & faster to build and update websites. The content management system was created to free content managers from distraction of multiple tools, the worry of steep learning curves, and a clear need to tell the right story, to the right audience, at the right time. Mura is loved by content managers, content contributors, marketers and developers alike.

A hybrid content management system that includes classic CMS and Headless CMS features. With dotCMS content managers can create content that fuels the brand experience. The API-first approach provided by the headless part of dotCMS allows developers to build extremely fast front-ends with popular third-party front-end framework and deliver content optimally. The content management system allows content creators to build engaging and memorable content that can be reused across sites.

Strapi is a free and open source headless CMS developed with JavaScript for Node.js. The software makes it really simple to generate REST and GraphQL APIs. Simply create your database schema and relationships in the Strapi admin panel UI, and Strapi will auto-generate API endpoints to represent the data structures provided. Strapi comes packed with features you come to expect from normal CMS's such as authentication, authorization, content management and a media library. The software can be used for free and can be self-hosted on any server and platform. Extra enterpise functionallity is currently being developed, and will be sold at cost.