Flarum is a free and open source web-based forum software, written in PHP and distributed under the MIT license. It is designed to be fast, simple, and highly extensible. Flarum provides a modern, powerful, and intuitive forum experience for users, and provides developers with an extensible platform to build on. With features such as user accounts, customizable profiles, discussion threads, private messaging, and much more, Flarum has been designed to help users create and manage their own online forums. It also has a large library of extensions and themes, allowing for further customization and personalization. Flarum is perfect for creating online communities and forums that are easy to use and highly customizable.
The two applications are very similar, but Discourse is more mature and has a richer feature set thanks to a more active and sustainable development.