Federated microblogging server.

Advanced forum / community solution based on Ruby and JS.

Delightfully simple forums. Next-generation forum software that makes online discussion fun again.

Knowledge-based community software. You can use it to quickly build your Q&A community for product technical support, customer support, user communication, and more.

Forum software built for the modern web.

Link aggregator for the fediverse (alternative to Reddit).

Distributed social networking server.

Decentralized app-like microblogging server/SNS for the Fediverse, using the ActivityPub protocol like GNU social and Mastodon.

Ethical photo sharing platform, powered by ActivityPub federation (alternative to Instagram).

Flexible kit for private social networks.

Lightweight and simple comment engine, which doesn't spy on users. It can be embedded into blogs, articles or any other place where readers add comments.

Lightweight commenting server written in Python and Javascript. It aims to be a drop-in replacement for Disqus.

Private alternative front-end to Reddit, with its origins in Libreddit.

Fully featured modern forum application that is fast, scalable and responsive.

Collaborative decision-making tool that makes it easy for anyone to participate in decisions which affect them.

Comment system built in Golang, providing a lightweight and highly customizable solution for adding comments to your website.

Flat-forum bulletin board software solution that can be used to stay in touch with a group of people or can power your entire website.

Modern, federated social network based on XMPP, with a fully featured group-chat, subscriptions and microblogging.

Better commenting experience from Vox Media.

Create a community, where your users can suggest ideas and get questions answered. And have friendly open-ended discussions and chat (Slack/StackOverflow/Discourse/Reddit/Disqus hybrid).

Social Communication Server.

Powerful social networking engine.

Social networking software that allows you to make a social networking website and helps your members build social relationships, with people who share similar professional or personal interests.

Free, extensible forum software package.

Stack Overflow in a JAR. An enterprise-ready Q&A platform with full-text search, SAML, LDAP integration and social login support.

Free, professional grade software package that allows you to set up your own online community within minutes.

Modern, multi-platform BBS engine with unlimited "callers" and legacy DOS door game support.

Privacy-friendly and customizable Disqus (comment system) alternate.

Q&A-based community knowledge-sharing software.

Federated and decentralized profile builder and social network engine.

Powerful plugin that takes your WordPress.org powered site beyond the blog with social-network features like user profiles, activity streams, user groups, and more.

Bridge that interacts with Fediverse on behalf of your static site.

Platform for Local Communities.

Federated microblogging server with Mastodon, GNU social, and ActivityPub compatibility.

Fast, SQLite-powered forum engine written in ASM.

ActivityPub federated social network server implementing the Mastodon client API.

Decentralized identity, privacy, publishing, sharing, cloud storage, and communications/social platform.

Federated microblogging server that communicates over ActivityPub.

Federated microblogging server, Mastodon, GNU social, & ActivityPub compatible.

Twitter™-like Decentralised micro-logging platform. No ads, no tracking, your content, your data.

Link aggregator / reddit clone for the fediverse (alternative to Reddit).