Fediverse
The fediverse is a network of independently run social apps, such as Mastodon, that interoperate through a shared protocol so users on different servers can follow each other.
The fediverse (short for federated universe) is a collection of separately run social platforms, including Mastodon, PeerTube, Pixelfed and WriteFreely, that all speak the same open protocol, mostly ActivityPub, so an account on one server can follow, reply to and share posts from an account on a completely different server. It works the way email does: different providers, one shared way of delivering messages.
No single company owns the fediverse, each server (called an instance) sets its own rules and moderation, and a user can move their account between instances without starting over. Threads has added partial fediverse integration through ActivityPub, letting opted-in users see and be seen by Mastodon accounts, though the reverse is not true for every Threads feature.
Bluesky is often confused with the fediverse but runs on a separate protocol (AT Protocol), not ActivityPub, so the two networks are related in spirit but not directly interoperable without a bridge service.
Examples
- A Mastodon account with 500 followers on a server called mastodon.social following and replying to a PeerTube creator hosted on a completely different server.
- A journalist moving their account and 2,000 followers from one Mastodon instance to another after a server shutdown.
Related terms
Threads is Meta's text-based conversation app, tied to an Instagram account, that is also opening up to the wider fediverse via ActivityPub.
Bluesky is a social network built on the open AT Protocol, which separates identity, data storage and feed ranking so anyone can run their own server.
The ranking system each platform uses to decide whose content appears in whose feed.