Discourse is a free, open-source community discussion platform, built in Ruby on Rails and licensed under GPL-2.0, for organisations and communities that want complete control over how and where their forum is run rather than renting a hosted service.

What it is

Discourse is a platform for community discussion, described by its maintainers as the online home for a community. It is a 100 percent open-source project that has been battle-tested for over a decade and continues to evolve. The back end is a Ruby on Rails application that responds to requests RESTfully in JSON, and the front end is an Ember.js application that communicates with that Rails API. PostgreSQL serves as the main data store, and Redis is used as a cache and for transient data. The project lives in the Ruby and JavaScript ecosystem, spanning the Rails, Ember, PostgreSQL and Redis topic areas, and it is developed in the open at github.com/discourse/discourse, with support community discussion hosted at meta.discourse.org.

The concrete problem it solves is ownership of community infrastructure. Long-running forums built on hosted or proprietary discussion services leave the operator dependent on someone else's pricing, roadmap and data handling. Discourse replaces that arrangement with software the operator can run on their own infrastructure, so topics, users and history remain under the operator's control. It also consolidates what would otherwise be several separate tools: threaded discussion, real-time chat, customisable theming and an extensible plugin system all ship in the same platform, which means a community does not need to bolt a chat service and a theme layer onto a basic forum package.

Key capabilities

• Discussion topics for structured, long-form conversation, persisted in PostgreSQL.
• Built-in real-time chat alongside the threaded forum.
• A theming system with an ever-growing selection of official and community themes.
• A plugin system, including Discourse AI for chatbot functionality and the Data Explorer plugin for SQL analysis.
• A RESTful JSON API served by the Rails back end, which the Ember.js front end consumes.
• Redis-backed caching and transient data handling.
• Support for the latest stable releases of Safari, Chrome, Edge and Firefox, plus iPadOS, iOS and Android tablets and phones, with Safari on iOS 16.4+ targeted.

Who uses it and how

• Communities that self-host Discourse on their own infrastructure when they want control of where the site runs.
• Teams that would rather skip setup, maintenance and server management and take official Discourse hosting instead.
• Operators migrating off hosted or proprietary forum services who want their discussion history to live in their own PostgreSQL database.
• Community teams extending the base forum with plugins, adding chatbots through Discourse AI or SQL analysis through the Data Explorer.
• Contributors working against the public repository and the Discourse support community at meta.discourse.org; contributions require reading CONTRIBUTING.MD and signing the Electronic Discourse Forums Contribution License Agreement.

Getting started

For production use, the README points to the Discourse Install Guide at docs/INSTALL.md, and for official hosting it points to discourse.org/pricing. For development, the project publishes setup guides for Docker, a Dev Container in VS Code (the recommended route), CLI, macOS, Ubuntu/Debian and Windows, requiring at minimum Ruby 3.4+, PostgreSQL 15 and Redis 7.

How it compares

No competing products are named in the facts supplied for this registry entry, so Discourse stands alone here among similar tools. The only comparison the material supports is internal to the project: self-hosting on your own infrastructure against official Discourse hosting, which removes the setup, maintenance and server management burden at a cost set out at discourse.org/pricing, versus the zero licence cost of running the open-source code yourself.

When to use it — and when not to

Self-hosters must operate a full stack, not a single binary: Ruby 3.4+ with Rails, PostgreSQL 15 as the main data store, Redis 7 for cache and transient data, and a container or dev-container workflow for setup. Anyone unwilling to run and maintain that infrastructure, and unwilling to pay for official hosting, should not pick it. Two further signals are worth weighing: the repository carries 221 open issues, and the README does not state a release schedule or point to release notes, so operators who need a predictable upgrade cadence should confirm that separately before committing.