Discourse

Discourse is the most widely deployed open-source forum software, used by more than 22,000 communities including OpenAI, GitLab, Zoom, and Asana. It reimagined what forum software should look like when it launched in 2013, and the design has held up: infinite scroll, real-time updates, a modern editor, and a trust-level system that rewards active contributors with expanded permissions over time.

Beyond basic discussion threads, Discourse has evolved into a broader community platform. Real-time chat (channels and direct messages) sits alongside the forum, a knowledge base mode lets you organize pinned answers into a wiki-style structure, and an events plugin handles community meetup coordination. A plugin ecosystem adds functionality ranging from voting and polls to SSO-based member gating.

The self-hosted version is completely free and GPL-licensed. Installation uses Docker Compose with an opinionated one-command setup, though the official install process is deliberately guided rather than flexible. The minimum server recommendation is 2GB RAM.

Managed hosting starts at $100/month for communities that want Discourse-operated infrastructure without the maintenance overhead. That plan covers 500k monthly page views and 20GB of storage.

The main trade-off with Discourse is that it is opinionated software. The design philosophy (no traditional pagination, aggressive email digests, trust levels) is well-thought-out but not customizable away without significant work. You use Discourse as Discourse, or you don’t.