Mastodon

Mastodon is a free, open-source social network server for publishing links, pictures, text, and video. It lets people follow friends, discover new ones, and run their own server while still joining a broader federated network. Servers interoperate through ActivityPub, so users on different servers can communicate across the Fediverse.

It provides real-time, chronological timeline updates, media attachments, private posts, locked accounts, phrase filtering, muting, blocking, reporting, and moderation tools. Mastodon also acts as an OAuth2 provider, with REST and Streaming APIs for third-party apps.

Because it is built on open standards, the network reaches beyond Mastodon itself: anything that implements ActivityPub is part of the same broader social web, so you can follow and be followed by people on other servers and other software. Mastodon ships with Docker and docker-compose configs and a standalone install path, running on Ruby on Rails with PostgreSQL, Redis, and Sidekiq.