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hongsheng yang
hongsheng yang

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FlatBB vs Discourse, Flarum, and phpBB: a lightweight PHP forum for shared hosting — and for AI

Most “modern” forum stacks assume you have Docker, Composer, Redis, and spare RAM. A lot of real communities only have cheap shared hosting and an FTP client. FlatBB is a free MIT-licensed forum in plain PHP 8.1+ aimed at that reality: unzip a folder, open the installer, pick SQLite or MySQL, and you’re live.

This post compares FlatBB with Discourse, Flarum, and phpBB/MyBB, then explains why its plugin system is deliberately AI-friendly.

Quick comparison

Discourse Flarum phpBB / MyBB FlatBB
Stack Ruby, Postgres, Redis, Docker PHP + Composer Classic PHP Plain PHP 8.1+
Install Container / launcher Composer / SSH often Upload + installer Unzip + browser installer
Hosting fit VPS 2–4GB+ Shared/VPS with Composer Shared hosting Cheapest shared hosting
UX Excellent modern Clean modern Dated by default Discourse-style three-column, dark mode, mobile
RTL / i18n Strong Often needs RTL extension Language packs Built-in packs + RTL mirroring (incl. Persian)
Extensibility Plugins Extensions Mods Plugins + marketplace
License GPL MIT GPL / LGPL MIT

vs Discourse

Discourse is the gold standard for large, active communities: moderation, trust levels, email digests, ecosystem. The trade-off is operational weight Docker, Postgres, Redis, and enough RAM that a $2–5 shared plan is out of the question.

Choose Discourse if you have a real VPS budget and need enterprise-grade community tooling.

Choose FlatBB if you want a modern-feeling board without containers same “community forum” goal, different hosting constraints.

vs Flarum

Flarum is elegant and lighter than Discourse, but many installs still expect Composer and a host that can run the PHP toolchain. Extensions are powerful; RTL historically needed extra work.

FlatBB keeps the “upload and go” path: no Composer, no build step. Language packs ship in the box (EN/DE/FR/ES/PT/IT/NL/FA). When a pack is RTL, layout, drawer, and icons mirror with dir="rtl". Posts follow their own writing direction for mixed communities.

vs phpBB / MyBB

Classic boards still win on familiarity and “just upload it.” FlatBB keeps that deploy model but ships a cleaner three-column UI, Markdown with live preview, FTS search, notifications, one-click upgrades, and a smaller plugin surface aimed at AI assistants.

AI-friendly by design

The part we’re most intentional about is plugins:

  • A plugin is one folder with a plugin.php manifest (routes, hooks, settings, admin pages, jobs).
  • The whole API fits in a single document: https://www.flatbb.com/dev/plugins.md
  • Paste that into Claude Code, Codex, or Cursor, describe the feature, and upload the zip in Admin → Plugins (or publish to the marketplace).
  • Naming, security (h(), CSRF), and SQL portability rules live in that same file so assistants dont invent host-specific SQL.

Every bundled plugin was built this way. Marketplace: https://www.flatbb.com/market

Who FlatBB is for

  • Small/medium communities on shared hosting or a tiny VPS
  • Admins who refuse Docker for a hobby forum
  • Multilingual / RTL communities (Persian, Arabic, Hebrew-ready layout mirroring)
  • Builders who want AI to scaffold plugins instead of reading 50 hook docs first

Links

MIT licensed. If you try it, tell us where it breaks the support forum runs on FlatBB itself.

Disclosure: I’m the author of FlatBB.

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