Flarum is a free, open-source PHP and Mithril.js forum platform. Explore its features, self-hosting requirements, extensions, pricing, and alternatives.
Flarum is a free, open-source discussion forum platform built with a PHP and Laravel-based backend and a Mithril.js single-page application frontend, released under the MIT license. It is designed to be installed on a site owner's own server using Composer, PHP's package manager, and is aimed at communities that want a fast, modern forum without the overhead of older, page-reload-based forum software.
The project traces back to a design philosophy Toby Zerner conceived around 2010 and prototyped by 2012, and it is commonly described as growing out of the lineage of two earlier PHP forum projects, FluxBB and esoTalk, reflecting the backgrounds of Zerner and FluxBB creator Franz Liedke, who both worked on the project in its early years. Flarum was open-sourced publicly in December 2014 after an initial Kickstarter campaign was canceled in favor of free distribution, and it reached its first stable 1.0.0 release on May 27, 2021, after an unusually long multi-year public beta period. Since 2019, the project has been led by Daniel Klabbers and is now legally owned by the nonprofit Flarum Foundation, registered in the Netherlands.
At its core, Flarum provides discussions organized by tags rather than traditional nested subforums, role-based groups and permissions, a Markdown and WYSIWYG-capable post editor, and real-time-feeling navigation powered by its single-page frontend. Notifications, mentions, and subscriptions are handled through bundled first-party extensions rather than being hardwired into the core, which keeps the base installation lean.
Almost every additional capability, such as social login, private messaging, advanced moderation and audit logging, search improvements, SEO tooling, and integrations with external services, is added through Flarum's Composer-based extension system, which exposes a documented Extension API for PHP and JavaScript developers. Hundreds of free community extensions are available on GitHub and Packagist, alongside an official premium extensions marketplace where invited developers sell more advanced add-ons directly to forum owners.
Flarum's backend is a PHP application that uses components from the Laravel framework and exposes a REST API that the frontend, and any external client, communicates with. The frontend was originally written in Ember.js when Flarum launched in 2015 but was later rewritten in Mithril.js, a smaller JavaScript framework, to keep the single-page interface lightweight.
Self-hosting Flarum requires a PHP-capable web server, a MySQL or MariaDB-compatible database, and Composer for installing the core and any extensions. The actively developed 2.x branch requires PHP 8.3 or newer as of 2026, while the long-lived 1.x branch, culminating in the 1.8.x series, remains compatible with PHP 7.3 and above and is still widely deployed on production forums that have not yet upgraded.
Yes. Flarum's core software is free and open source under the MIT license, and it can be downloaded, self-hosted, and modified at no cost. Some advanced functionality is available only through optional paid premium extensions sold by independent developers on Flarum's marketplace.
No. Flarum does not operate an official paid hosting service; an early plan to pair a hosted offering with its 2014 Kickstarter campaign was dropped in favor of pure open-source distribution. Site owners who do not want to self-host can use independent third-party managed-hosting providers such as Elestio, 20i, TMDHosting, or 365i.
Flarum's backend is written in PHP using components from the Laravel framework, and its frontend is a single-page application built with the Mithril.js JavaScript framework. Extensions and themes are distributed and installed as Composer packages.
Toby Zerner conceived Flarum's design philosophy around 2010 and built early prototypes by 2012. The project was publicly open-sourced in December 2014 after Zerner canceled a Kickstarter campaign, and Franz Liedke, creator of the earlier FluxBB forum software, joined the effort in March 2015. Flarum reached its first stable 1.0.0 release on May 27, 2021.
Compared to Discourse, Flarum is generally lighter to self-host and does not push users toward a paid hosted plan. Compared to phpBB, Flarum offers a more modern single-page interface instead of full-page reloads. Both Discourse and phpBB have larger, longer-established extension and plugin ecosystems in certain areas.
Flarum is led by Daniel Klabbers and is legally owned by the Flarum Foundation, a nonprofit entity (registered in the Netherlands as Stichting Flarum) established after original creator Toby Zerner stepped back from the project in July 2019 to pursue a separate premium forum software venture.