Open-source social networks and forum software

Software for running your own online community, from a Twitter-style network that federates with the wider Fediverse to forums built around threaded discussions.

18 open-source projects, checked against GitHub on 12 November 2026.

All 18 social networks & forums projects

Showing all 18, ordered by health score.

  1. 88 Active
    Mastodon

    Your self-hosted, globally interconnected microblogging community

    AGPL-3.0
    Setup
    3 of 5
    Stars
    50.6k
    Release
    3 November 2026
  2. 81 Active
    Misskey

    A completely free and open interplanetary-microblogging platform

    AGPL-3.0 relicensed 2018
    Setup
    2 of 5
    Stars
    11.4k
    Release
    12 November 2026
  3. 81 Active
    HumHub

    HumHub is an Open Source Enterprise Social Network. Easy to install, intuitive to use and extendable with countless freely available modules.

    AGPL-3.0 CLA
    Setup
    From source
    Stars
    6.8k
    Release
    9 November 2026
  4. 81 Active
    remark42

    comment engine

    MIT
    Setup
    1 of 5
    Stars
    5.6k
    Release
    11 October 2026
  5. 80 Active
    NodeBB

    Node.js based forum software built for the modern web

    GPL-3.0 CLA
    Setup
    3 of 5
    Stars
    15.2k
    Release
    31 October 2026
  6. 80 Active
    PixelFed

    Photo Sharing. For Everyone.

    AGPL-3.0
    Setup
    4 of 5
    Stars
    7.1k
    Release
    21 October 2026
  7. 77 Active
    Movim

    Movim - Decentralized social platform

    AGPL-3.0
    Setup
    From source
    Stars
    2.1k
    Release
    4 November 2026
  8. 76 Active
    Loomio

    Loomio is a collaborative decision-making tool

    AGPL-3.0
    Setup
    4 of 5
    Stars
    2.6k
    Release
    7 November 2026
  9. 74 Active
    Lemmy

    A decentralised discussion platform for communities.

    AGPL-3.0
    Setup
    3 of 5
    Stars
    14.7k
    Release
    26 October 2026
  10. 73 Active
    Discourse

    A platform for community discussion. Free, open, simple.

    GPL-2.0 CLA
    Setup
    From source
    Stars
    48.1k
    Release
    15 July 2026
  11. 68 Active
    Answer

    A Q&A platform software for teams at any scales. Whether it's a community forum, help center, or knowledge management platform, you can always count on Apache Answer.

    Apache-2.0
    Setup
    1 of 5
    Stars
    15.7k
    Release
    9 October 2026
  12. 61 Active
    Coral

    A better commenting experience from Vox Media

    Apache-2.0
    Setup
    2 of 5
    Stars
    2k
    Release
    6 November 2026
  13. 58 Active
    phpBB

    phpBB Development: phpBB is a popular open-source bulletin board written in PHP. This repository also contains the history of version 2.

    GPL-2.0
    Setup
    Docker
    Stars
    2.1k
    Release
    None
  14. 54 Active
    Artalk

    Your Self-hosted Comment System. | 自托管评论系统

    MIT relicensed 2023
    Setup
    1 of 5
    Stars
    2.4k
    Release
    25 October 2026
  15. 52 Active
    Isso

    a Disqus alternative

    MIT
    Setup
    2 of 5
    Stars
    5.3k
    Release
    26 March 2026
  16. 50 Active
    Redlib

    Private front-end for Reddit

    AGPL-3.0
    Setup
    1 of 5
    Stars
    4k
    Release
    22 October 2026
  17. 41 Active
    Flarum

    Simple forum software for building great communities.

    MIT
    Setup
    From source
    Stars
    16.4k
    Release
    9 October 2026
  18. 28 Slowing
    diaspora*

    A privacy-aware, distributed, open source social network.

    AGPL-3.0
    Setup
    3 of 5
    Stars
    13.7k
    Release
    7 April 2026

Our picks by use case

  • A Twitter-style network on your own domain

    Mastodon runs a microblogging server whose members can follow and reply to accounts across the Fediverse over ActivityPub.

  • A full-featured community forum

    Discourse combines threaded topics with built-in chat, themes and plugins, and fits product, open-source and customer communities.

  • A light forum on PHP hosting

    Flarum keeps a clean, minimal layout that works the same on phones and desktops, and adds features through extensions.

  • Communities that build on an API

    Mastodon offers REST and streaming APIs that existing mobile and desktop clients use, and Discourse serves JSON from its Rails back end.

How to choose a social network or forum

The basic choice is between a timeline and a forum. Timelines suit short public posts and following people, while forums keep longer conversations sorted by topic so that newcomers can find old answers.

Timeline or threads

On Mastodon, posts arrive in a chronological feed and older conversations scroll away. Discourse and Flarum file discussions under topics, which works better for support questions, documentation and debates that people come back to weeks later.

Federation

A Mastodon server is not a closed site: its members can follow people on other servers, and those servers can reach yours. That widens the audience, but moderators then look after federation as well as their own users. Discourse and Flarum stand on their own.

Hosting requirements

Flarum runs on ordinary PHP hosting, and its repository ships no Docker image. Discourse installs with one command and needs Ruby, PostgreSQL 18 or newer and Redis 7. Mastodon asks the most, with PostgreSQL, Redis, Sidekiq workers, media storage and FFmpeg to maintain.

Extensions and upgrades

Both forums lean on add-ons. Flarum 2.0.0 shipped in October 2026, so confirm that the extensions you depend on support it. Discourse plugins range from the Data Explorer for SQL queries to Discourse AI.

License and contributions

Flarum is MIT-licensed, Mastodon is AGPL-3.0 and Discourse is GPL-2.0 or later, and none of these repositories holds paid parts. Discourse asks contributors to sign a CLA, and its company sells hosting plans, including a free tier, for groups that would rather not run a server.

Drafted with AI from the projects’ READMEs and our data, then checked against that data on 7 November 2026. Report a correction

Which of these are really open source?

Fully open source (18)OSI-approved license, no paid parts in the repository
Mastodon, Discourse, Flarum, Answer, NodeBB, Lemmy, diaspora*, Misskey, PixelFed, HumHub, remark42, Isso, Redlib, Loomio, Artalk, phpBB, Movim, Coral
Open source with paid parts (0)OSI license, but some features are under commercial terms
None
Not OSI open source (0)Code is public, use is restricted
None
License changesNewest first
Artalk: LGPL → MIT, 2023; Misskey: MIT → AGPL-3.0, 2018

Read automatically from each repository’s license files every day. How we read licenses

Questions about open-source social networks & forums

What are the most popular open-source social networks & forums projects?

By GitHub stars: Mastodon (50.6k), Discourse (48.1k), Flarum (16.4k). By our health score, the most actively maintained are Mastodon (88), Misskey (81), HumHub (81).

Which social networks & forums projects are fully open source?

18 of the 18 use an OSI-approved license with no paid parts in the repository, including Mastodon, Discourse, Flarum.

Which are the easiest to self-host?

Judged by the services in their compose files, Answer, Misskey, remark42, Isso need the least setup.

Which projects have changed their license?

Misskey (to AGPL-3.0 in 2018), Artalk (to MIT in 2023). Each project page links to the commit that made the change.

Other categories