Lemmy
Lemmy is an open-source, self-hostable link aggregator and forum for the Fediverse — a decentralised alternative to Reddit, Hacker News and Lobste.rs. You subscribe to communities you care about, post links and start discussions, then vote and comment on them, much as you would on a centralised site. The crucial difference is underneath: anyone can run a Lemmy server, and every server is federated (think email), so a user registered on one instance can subscribe to communities on any other and hold conversations with people registered elsewhere. It is written in Rust with Actix and Diesel on the backend, an Inferno/TypeScript front-end, and is licensed under the GNU Affero General Public License v3.0.
Key Features
- Federation via ActivityPub — Every instance joins the wider Fediverse, so communities and users are not trapped inside one company’s platform.
- Easy self-hosting — Ships with Docker and Ansible deployment options, plus a clean, mobile-friendly web interface.
- Familiar voting model — Full vote scores shown as (+/-) like old Reddit, with live-updating comment threads.
- Low-friction sign-up — Only a username and password are required to create an account; user avatars are supported.
- Themes and emoji — Light, dark and solarized themes, emoji autocomplete, and user tagging with @ and community tagging with !.
- Rich posts — Integrated image uploading in posts and comments, and a post can combine a title with self text, a URL, or both.
- Notifications and messaging — Replies and mentions trigger notifications, optionally delivered by email, along with private messaging.
- Syndication and discovery — RSS/Atom feeds for All, Subscribed, Inbox, User and Community, cross-posting support, and a similar-post search that is ideal for question and answer communities.
- Serious moderation tooling — Public moderation logs, sticky posts, site admins and community moderators who can appoint others, plus locking, removal, restoration, bans and account/community transfers.
- Data control — Users can fully erase their own data, replacing all their posts and comments; NSFW posts and communities are supported.
Why Use Lemmy?
Lemmy is the strongest option if your main concern is ownership and reach rather than raw feature count. Instead of building an isolated forum that only exists on your domain, you run an instance that is part of a federated network — so a small, self-hosted community can still be discovered by, and interact with, users across hundreds of other servers. Because it is AGPL-licensed, Rust-based and packaged for Docker and Ansible, it is straightforward to deploy and reasonably light on resources for a modern server.
Use Cases
- Communities leaving centralised aggregators who want a Reddit-style discussion space they control
- Topic or regional instances that should interconnect with the wider Fediverse rather than stand alone
- Organisations and hobby groups running a moderated, federated noticeboard and discussion forum
- Privacy-conscious users who want voting, threaded discussion and community moderation without corporate accounts or tracking
Alternatives
- Discourse — A centralised but far more feature-complete forum platform with built-in chat and a large plugin ecosystem.
- NodeBB — Node.js forum software with real-time updates and a traditional category-and-topic structure.
- Flarum — A minimalist PHP forum focused on speed and a clean interface.
- Mastodon — Federated microblogging on the same ActivityPub protocol, complementary to a Lemmy instance.
- Mbin and PieFed — Other Fediverse link-aggregator platforms that interoperate with Lemmy communities.
Platform
Self-hosted · Linux server (Docker or Ansible deployment) · Rust backend (Actix, Diesel) · PostgreSQL · Web and mobile browsers · Any ActivityPub-compatible Fediverse client
Licence
GNU Affero General Public License v3.0