MyBB

MyBB is forum software for building and running discussion boards. It is written in PHP and gives site owners a free, open source bulletin board they host themselves, with no per-seat fees or hosted dependency.

The data layer is flexible: MyBB runs on MySQL or MariaDB, PostgreSQL, or SQLite, so you can match it to whatever database your server already uses. Each release on the download page is a stable, production-ready build.

A board can be tailored with plugins, themes, and translations, letting administrators change behavior, appearance, and language without touching the core. MyBB is distributed under the GNU LGPL v3.