phpBB

phpBB is a free, open‑source bulletin board written in PHP that can be installed on a self‑hosted server. It provides the classic flat‑forum structure, allowing users to create topics, post replies, and organize discussions within a website or a dedicated community space. The software is released under the GPL‑2.0 license, requires no subscription, and includes a free tier suitable for small to medium groups.

The project offers extensive documentation for developers, including guidelines for contributing code, building development environments with tools such as Vagrant or GitHub Codespaces, and running automated unit and functional tests. Continuous integration is handled through Bamboo and GitHub Actions, ensuring stability across development branches. Community support and resources are available through phpBB.com and the Area51 development portal.

phpBB targets administrators and developers who need a customizable, self‑hosted forum solution that can be extended with extensions and integrated into existing web platforms while remaining freely available and actively maintained.