# Lemmy — Federated Link Aggregator for the Fediverse

> Self-hosted, federated link aggregation and discussion platform compatible with ActivityPub, offering a decentralized alternative to Reddit.

## Install

Save as a script file and run:

# Lemmy — Federated Link Aggregator for the Fediverse

## Quick Use
```bash
# Docker Compose deployment
git clone https://github.com/LemmyNet/lemmy-ansible.git && cd lemmy-ansible
# Or use Docker directly:
mkdir lemmy && cd lemmy
wget https://raw.githubusercontent.com/LemmyNet/lemmy/main/docker/docker-compose.yml
wget https://raw.githubusercontent.com/LemmyNet/lemmy/main/docker/lemmy.hjson
# Edit lemmy.hjson with your domain and database settings
docker compose up -d
```

## Introduction
Lemmy is a self-hosted link aggregation and discussion platform for the fediverse. Built in Rust with an Inferno.js frontend, it federates with other Lemmy instances and ActivityPub-compatible services like Mastodon, letting communities share content across a decentralized network without any single point of control.

## What Lemmy Does
- Hosts communities (subreddit-like groups) with link posts, text posts, and image uploads
- Supports threaded comment discussions with voting, sorting, and moderation tools
- Federates with other Lemmy instances and ActivityPub services for cross-instance interaction
- Provides moderation tools including community-level mods, site admins, and content filters
- Offers user profiles with post history, saved items, and subscription management

## Architecture Overview
Lemmy's backend is written in Rust using Actix-web, with Diesel as the ORM for PostgreSQL. The frontend is a server-side-rendered Inferno.js application. Federation is handled through the ActivityPub protocol, with outgoing activities queued and incoming activities validated against instance allow/block lists. Pictrs handles image hosting and thumbnailing as a separate service.

## Self-Hosting & Configuration
- Deploy via Docker Compose with the official images for lemmy, lemmy-ui, postgres, and pictrs
- Or use the lemmy-ansible playbook for automated deployment on a VPS
- Configure lemmy.hjson for hostname, database, email, federation, and rate limiting
- Set up a reverse proxy with Nginx for SSL termination and WebSocket support
- Enable email via SMTP for user verification and password resets

## Key Features
- Full ActivityPub federation connecting thousands of instances worldwide
- Customizable community rules with per-community and site-wide moderation
- Multiple sort algorithms including Active, Hot, New, and Scaled ranking
- Cross-posting between communities and cross-instance community subscriptions
- RSS feeds for communities, users, and site-wide content

## Comparison with Similar Tools
- **Reddit** — Largest link aggregation platform; centralized and proprietary
- **Kbin / Mbin** — Fediverse magazine-style aggregator; PHP-based with a different UX approach
- **Discourse** — Feature-rich forum software; not federated and focused on long-form discussion
- **Lobsters** — Invite-only link aggregator for computing; single-instance, not federated
- **Mastodon** — Federated microblogging; designed for short posts rather than link aggregation

## FAQ
**Q: Can users on my Lemmy instance interact with other instances?**
A: Yes. Through ActivityPub federation, users can subscribe to communities, vote, and comment on any federated instance.

**Q: How does moderation work across federated instances?**
A: Each instance has its own admins and community moderators. Instances can also block other instances entirely or filter specific content.

**Q: What are the server requirements for running Lemmy?**
A: A small instance runs comfortably on 2 CPU cores, 2GB RAM, and 20GB storage. Larger instances need more resources for database and media handling.

**Q: Can I migrate from Reddit to Lemmy?**
A: There are community tools for importing Reddit post histories, but federation means you can participate across the network from any single account.

## Sources
- https://github.com/LemmyNet/lemmy
- https://join-lemmy.org/docs

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Source: https://tokrepo.com/en/workflows/5e4b7e44-3cb4-11f1-9bc6-00163e2b0d79
Author: Script Depot