// the find
LemmyNet/lemmy
🐀 A decentralised discussion platform for communities.
Lemmy is a self-hostable Reddit alternative built on ActivityPub, meaning communities on different servers can federate with each other across the fediverse. It's written in Rust with Actix on the backend and runs well on low-power hardware including Raspberry Pi. The target audience is anyone who wants to run a community discussion platform without handing control to a corporation.
The federation story is the real differentiator — ActivityPub integration means your Lemmy instance is a first-class citizen of the broader fediverse, not just a Reddit clone running in isolation. The Rust backend is genuinely fast and the arm64 support means you can run a small community on a $15 Pi. The moderation toolset is unusually complete for an open-source project: public mod logs, per-community moderators, site-wide admins, ban/unban, and content removal are all there. The API has both a v3 (Reddit-compatible-ish) and native route layer, which makes building third-party clients straightforward, and there's a healthy ecosystem of clients already.
Federation debugging is a black box — when ActivityPub delivery fails between instances, there's no good tooling to diagnose why, and the error surface area is enormous because every other fediverse server implements the spec slightly differently. The frontend (lemmy-ui, a separate repo) has historically lagged behind backend features and the React/Inferno split has caused confusion; it's usable but not polished. Self-hosting setup is more involved than it looks — the Docker Compose setup works, but getting federation, image proxying, HTTPS, and email all working correctly requires touching a lot of config that isn't well-documented end-to-end. Spam and bot abuse is a genuine operational problem on public instances; the built-in defenses (CAPTCHA, registration applications) work but require active admin attention and there's no built-in rate limiting sophisticated enough to stop a determined bad actor.