Lightweight, extensible forum platform built in PHP with a Mithril.js frontend, supporting MySQL/MariaDB/PostgreSQL/SQLite and an active extensions ecosystem.

16.4k stars1.7k forksMITlast commit Actively maintained

Cloud-hosted discussion forum platform for building and moderating online communities. Provides topics, categories, threaded replies, trust levels, moderation and anti-spam tools, notifications, SSO and integrations, plugin ecosystem, and import/export capabilities.
Lightweight, extensible forum platform built in PHP with a Mithril.js frontend, supporting MySQL/MariaDB/PostgreSQL/SQLite and an active extensions ecosystem.

16.4k stars1.7k forksMITlast commit Actively maintained
Apache Answer is a modern open-source Q&A platform for teams to build knowledge bases, forums, and help centers.

15.6k stars1.3k forksApache-2.0last commit Actively maintained
Apache Answer is an open-source Q&A platform for community forums, help centers, and internal knowledge sharing with tagging, voting, and a plugin system.

15.6k stars1.3k forksApache-2.0last commit Actively maintained
NodeBB is a modern forum platform with real-time discussions, built-in chat, SSO options, plugins, and flexible theming, backed by Redis, MongoDB, or PostgreSQL.

15.2k stars3k forksGPL-3.0last commit Actively maintained
Open-source intranet and enterprise social network for communication, collaboration, and knowledge sharing with a modular, extensible design.

6.7k stars1.7k forkslast commit Actively maintained
Misago is a modern, fast forum application built with Python, Django, and React, featuring moderation tools, permissions, private threads, polls, and API integrations.

2.8k stars550 forksGPL-2.0last commit Actively maintained
Loomio is a collaborative decision-making tool for group discussions, proposals, and polls, helping teams make transparent decisions asynchronously with a clear record.

2.6k stars703 forksAGPL-3.0last commit Actively maintained
phpBB is an open-source forum (bulletin board) platform in PHP for building and managing community discussion boards with extensible theming and add-ons.

2.1k stars1k forksGPL-2.0last commit Actively maintained
RetroShare is a decentralized friend-to-friend platform for encrypted chat, mail, forums, channels and secure file sharing, with optional Tor/I2P support.

2k stars322 forkslast commit Actively maintained
Self-hostable community discussion platform combining Q&A, forums, team chat, ideation/upvoting, and Disqus-style embedded blog comments.

1.8k stars128 forksAGPL-3.0last commit Actively maintained
MyBB is a PHP-based, open-source forum platform with plugins, themes, moderation tools, private messaging and multi-database support.

1.2k stars439 forksLGPL-3.0last commit Actively maintained
Open source Stack Overflow clone for teams: Q&A, knowledge sharing, search, spaces, reputation, webhooks, and integrations via a Para backend.

921 stars230 forksApache-2.0last commit Actively maintained
Open-source PHP forum software supporting MySQL, PostgreSQL, or SQLite with a modular package system and rich moderation features.

744 stars270 forkslast commit Actively maintained
Modern Node.js-based BBS server with Telnet/SSH/WebSocket access, theming and mods, message networks, file areas, doors, and strong authentication options.

656 stars121 forksBSD-2-Clauselast commit Actively maintained
Mbin is a federated content aggregator offering voting, discussion and microblogging via ActivityPub. A community-focused fork of kbin, built with PHP and Symfony.

425 stars32 forksAGPL-3.0last commit Actively maintained
A modern forum, wiki, and community hub for discussions, curated lists, and knowledgebases. Extensible, secure platform built with TypeScript and Go.

324 stars37 forksMPL-2.0last commit Actively maintained
AsmBB is a lightweight, assembly-language web forum engine that runs via FastCGI and stores data in SQLite, designed for Linux servers and high performance.

Activity unknown
Open source ActivityPub-powered federated forum and link aggregator for running and joining community discussions across the Fediverse.

Activity unknown
Every option on this page is open source and free to run on your own hardware, so you own the data and there is no subscription to cancel. 16 of 18 shipped a commit in the last six months. Licences in this list: MIT, Apache-2.0, GPL-3.0, GPL-2.0, AGPL-3.0. In exchange you take on hosting, backups and updates yourself.
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