We wrote the Thredded forums engine focusing on these things:<p>1. Client-side performance. Little JavaScript and lean CSS. Even the KaTeX math plugin renders math server-side.<p>2. Clean but discoverable UI. The focus is content. Not a single dropdown nor a hamburger menu.<p>3. Extensible, but critical features are built-in to provide a foundation for plugins. Features such as notifications, moderation, permissions system, and full text search.<p>4. Pleasant on mobile for both browsing and content creation. This means a textarea instead of a rich text editor (by default).<p>5. Everything degrades gracefully when JavaScript is off. For example, preview-as-you-type becomes a "Preview" button if JavaScript is disabled.<p>6. The relational database for everything, including full text search. Data integrity is easy, no out-of-sync elasticsearch databases here. Runs on Postgres, MySQL, and SQLite.<p>Boring technology => easy to deploy and run in production.<p>The codebase is written in Ruby, has slowly developed over the years, and has extensive test coverage.<p>I am very curious to hear what you think, and whether you've ever felt a need for a forum like that.