Open-source Reddit alternatives

Discourse is a fully open-source platform for online community discussion. It is aimed at those who prefer to decide for themselves how and where their site runs, and it is written mainly in Ruby on Rails with a JavaScript front end and PostgreSQL. It is released under the GPL-2.0 license.

Discourse lets you start discussion topics, talk live through its integrated chat, change the look with official and community themes, and extend the site with plugins, ranging from chatbots powered by Discourse AI to the Data Explorer plugin for SQL analysis. Current stable versions of the major browsers are supported across desktops, tablets and phones.

You can self-host it on your own infrastructure by following the install guide, or choose the official Discourse hosting if you would rather skip setup and server management. Development setups use Docker or a VS Code dev container and need Ruby, PostgreSQL and Redis. It suits companies, open-source projects and groups running forums and support communities.

Forem is open-source software for building communities for peers, customers, fanbases, families, friends or any group that wants a shared space. It is the codebase behind dev.to, a community of software developers who write articles, discuss and build professional profiles. The project is written in Ruby on Rails and released under the AGPL-3.0 license.

The repository includes installation documentation, developer documentation and instructions for deploying with Kamal. Contributors are welcome to open pull requests on any issue, provided they include appropriate tests, with the maintainers currently focused on backend regression tests while frontend changes may need more user review. The project states that AI-assisted pull requests are welcome if they meet quality standards, and it points AI agents to an AGENTS.md file. A vulnerability disclosure process and acknowledgements are also documented.

NodeBB is forum software built on Node.js that keeps the traditional bulletin board format, with category hierarchies, local user accounts and asynchronous messaging, while adding modern features. It uses web sockets for instant interactions and real-time notifications, is mobile responsive, and exposes rich RESTful read and write APIs.

It supports Redis, MongoDB or PostgreSQL as its database. The core contains a common set of basic functionality, and additional features and integrations come from third-party plugins. A theming system extends base templates and styles with SCSS or CSS, and the base theme uses Bootstrap 5. A minimalist theme called Harmony is available for getting started without coding.

NodeBB is released under the GPL-3.0 license and is self-hosted. It requires a recent Node.js release (version 22 or later) plus MongoDB 5 or later or Redis 7.2 or later. Translations are managed with Transifex, and the project invites developers, designers and translators to contribute.

Lemmy is an open-source link aggregator and discussion forum that belongs to the fediverse. Users subscribe to communities, post links and text, vote and comment, much as they would on Reddit, Lobste.rs or Hacker News, but the software is decentralized and anyone can run a server.

Servers federate with each other in a way comparable to email, so someone registered on one instance can subscribe to communities and join conversations on others. Each server sets its own moderation policy, with site-wide admins and community moderators. Features include live-updating comment threads, vote scores, themes, avatars, a mobile-friendly interface and sign-up that needs only a username and password.

As an open-source alternative to Reddit and other link aggregators, Lemmy puts control in the hands of whoever runs the server rather than a single company. The backend is written in Rust using Actix and Diesel, with a TypeScript front end, and it is licensed under AGPL-3.0. Deployment is supported through Docker and Ansible.

This repository holds the source code of Lobsters, a computing-focused community built around link aggregation and discussion. It is a Rails application that uses SQL for storage, with SQLite in production, and is open source as part of the project's commitment to transparency.

The code has been used to run sister sites, but the main aim is to let people understand and improve the site itself. Contributors are asked to read the CONTRIBUTING file for setup, and a chat room usually has someone familiar with the code. The team describes a conservative philosophy: use Rails features over custom code, avoid new production services and external dependencies, and self-host from the VPS up.

Lobsters began on Rails 3.2.2 in 2012 and is run as a volunteer project with a long time horizon. Tests focus on core functionality, and the team accepts occasional downtime for large changes. It is the codebase of a specific community site rather than a general-purpose product, so it mainly interests developers who want to study or contribute to it.

Mbin is a decentralized content aggregator, voting, discussion and microblogging platform that runs on the fediverse. It speaks ActivityPub, so it can exchange content with services such as Mastodon, Lemmy, Pixelfed, Pleroma and PeerTube. It is a community-focused fork and continuation of kbin.

Compared with its origin, the project lists interface improvements, general enhancements, bug fixes, support for all ActivityPub actor types including service accounts for bots, up-to-date PHP packages with security fixes, and support for the application/json Accept header on ActivityPub endpoints. Hosted documentation is published at docs.joinmbin.org.

Mbin is written in PHP using the Symfony framework and is licensed under AGPL-3.0. For people running a server, there are guides for bare-metal or VM installs as well as Docker, and the repository enables security advisories, Dependabot and code scanning. Governance is shared: maintainers merge pull requests after consensus on Matrix, following the Collective Code Construction Contract, with translations managed through Weblate. Public instance lists are available for users who just want to join.