Lemmy is an open-source, easily self-hostable link aggregator that you can use to share and discover interesting new ideas and discuss them with the world. It is designed to work in the Fediverse, and communicate natively with other ActivityPub services, such as Mastodon, Funkwhale and Peertube.
Lemmy aims to create a decentralized alternative to widely used proprietary services like Reddit. For a link aggregator, this means a user registered on one server can subscribe to communities on any other server, and have discussions with users registered elsewhere. The front page of popular link aggregators is where many people get their daily news, so Lemmy has the potential to help alter the social media landscape.
Lemmy is self-hostable. Generic docs: join-lemmy.org/docs, configuration. Self-hosted instances (examples: lemmy.hacktivism.ch, lemmy.ml, slrpnk.net).
Lemmy runs on infrastructure communities control—no single canonical host. The live instances below are examples only; deploy your own with the generic docs.
Generic (Lemmy project): join-lemmy.org/docs —
Docker install,
configuration
(lemmy.hjson: hostname, database, pictrs, federation).
Example instances (live):
| Instance | Notes |
|---|---|
| lemmy.hacktivism.ch | one self-hosted deployment; setup docs and config example document this instance only |
| lemmy.ml | long-running project instance |
| slrpnk.net | solar / climate community |
Link aggregators are a form of social infrastructure: communities gather around shared topics, and a single corporate platform can control ranking, moderation, reach, and account access for millions of users at once.
Lemmy distributes this power across federated instances. Communities set their own rules, voting is transparent, and users can subscribe across servers without surrendering their identity to a global surveillance graph. It offers an escape from Reddit-style monopoly, opaque ranking, and the lock-in that comes with building a community inside a proprietary silo.
A school example, not only install links. Same constraints as social media in schools: closed class, staff who can moderate today, no ads or ranking of pupils.
Who. A subject class or club (history, climate, FOSS) that today dumps links in a class WhatsApp and a public-ish Reddit or Discord. Families should not need Meta accounts; pupils should not be a public audience.
Where (example host, not mandatory). A school-run Lemmy, or a locked-down instance you trust. lemmy.hacktivism.ch is one live example of self-hosting — not a school enrolment server. Ops notes for that host: Lemmy README. Generic: join-lemmy.org/docs.
First hour in class (staff + two pupil mods).
!class9a@school.example (local community, not
federated to the public Fediverse unless the school policy says so).Works. The class URL is !class9a@instance. If the school later
moves host, the community can move; Reddit cannot.
Fails. An open, federated default will leak pupil posts. Lock federation (or do not federate that community) unless legal/staff said otherwise. Empty boards stay empty — a teacher still has to post the first links.
Walkthrough: Lemmy school scenario.