Top 10 open source CMS for building a website

When you think about content management systems, WordPress is the first that comes in mind. Besides powering more that 30% of all websites in the world, WordPress is very user-friendly, has a large community and a lot of free and paid ressources like themes, plugins and tutorials ...
WordPress can also be used as an e-commerce platform with WooCommerce but I'll talk about that in an upcoming list about e-commerce solutions.

Joomla is for those who are looking for a little bit of a challenge, at least in terms of coding power. In many ways, Joomla has been built with medium to large sized sites in mind. Joomla’s code base is much more sophisticated than that of WordPress, but it comes at the benefit of more scalability and more back-end integration.
Regardless of the kind of business you operate, you need to maintain your website in a proper way to create a good impression with potential customers. Small businesses reputed Joomla as the best option for their needs. This open source platform is easily customized and handled. There are lots of themes and extensions available for Joomla.

Drupal goes even deeper into the architecture of the content management system itself, and because of how widely adopted it is to professional coding standards, a lot of engineer and developer-type webmasters have adapted to Drupal as their primary content management platform. Drupal offers more than 30,000+ extendable modules to bring your site to a whole new level, as well as 2,500+ individual and unique themes that will help to build the site that you’ve always wanted to build. Thousands of members participate in daily forum discussions, meaning that finding support for Drupal is really not a problem, rather a question of whether you really need help or are there resources available that can solve your problem without having to visit the community forums.

MODX is a content management system that was first released in 2005 by Ryan Thrash, Raymond Irving and Jason Coward. They created it to give them freedom of design and yet retain robust security which they felt other CMSs didn’t allow.
If your website is critical to your business, MODX delivers power and creative freedom. Freedom for designers, freedom for non-technical content authors and freedom for your site to grow and change with your business. Web pros get a customizable core to fit almost any requirement or scale. Whether it be a multi-domain global presence, a mobile API, or anything in between, MODX meets your needs today—and tomorrow.

ProcessWire is a content management system (CMS) distributed under the Mozilla Public License version 2.0 (MPL) and MIT License. It is designed from the ground up to tackle the issues caused by exactly this kind of opinionatedness (which, inevitably, results in frustrated developers and users) by being — you guessed it — non-opinionated. At its heart, it is based on a few simple core concepts and offers an exceptionally easy-to-use and powerful API to handle content of any kind.

Grav is a fast, simple and flexible file-based web-platform. There is zero installation required. Just extract the ZIP archive, and you are already up and running. It follows similar principles to other flat-file CMS platforms, but has a different design philosophy than most. Grav comes with a powerful package management system to allow for simple installation and upgrading of plugins and themes, as well as simple updating of Grav itself.
The underlying architecture of Grav is designed to use well-established and best-in-class technologies to ensure that Grav is simple to use and easy to extend.
Some of these key technologies include Twig templating, Markdown, YAML and much more.

Jekyll is a simple, blog-aware, static site generator perfect for personal, project, or organization sites. Think of it like a file-based CMS, without all the complexity. Jekyll takes your content, renders Markdown and Liquid templates, and spits out a complete, static website ready to be served by Apache HTTP Server, nginx or another web server. Jekyll is the engine behind GitHub Pages, which you can use to host sites right from your GitHub repositories.
Jekyll does what you tell it to do — no more, no less. It doesn't try to outsmart users by making bold assumptions, nor does it burden them with needless complexity and configuration. Put simply, Jekyll gets out of your way and allows you to concentrate on what truly matters: your content.

Ghost is a free, open source, hackable and simple yet powerful blogging or online publication software written in Node.js. It is a collection of modern publishing tools designed for easily building and running online publications.

Anchor is a super-simple, lightweight blog system, made to let you just write.
Anchor gives you full freedom over your words. Just write in Markdown or HTML, whatever you prefer.

Pagekit is a modular and lightweight CMS built with Symfony components and Vue.js + many more modern tools like Composer, Doctrine, UIkit, jQuery, Gulp.js, Webpack and other open source projects. It gives you the tools to create beautiful websites. All wrapped up in a clean and intuitive user interface.