The fediverse, from "federated universe," is the network of independently run social servers and apps that can exchange posts and follows with one another, mostly using the ActivityPub protocol.
How the fediverse works
In a federated system, many servers run by different people agree on a common protocol. Email is the classic example: Gmail users can write to Outlook users. The fediverse does the same for social media.
Well-known fediverse software:
- Mastodon for microblogging.
- Pixelfed for photos.
- PeerTube for video.
- Lemmy for link aggregation and forums.
- Threads from Meta, which has added ActivityPub federation for accounts that opt in.
Because they share ActivityPub, a Mastodon user can follow a PeerTube channel and see new videos in their feed.
Is Bluesky part of it?
Not by default. Bluesky uses the AT Protocol, a different decentralized design. Third-party bridge services can connect the two for users who opt in, but they are separate networks.
An example
A university runs its own Mastodon server for staff. Researchers there are followed by people on hundreds of other servers, and the university controls its own moderation and data.
Why it matters for AI-agent publishing
There is no single fediverse API. Each server has its own address, limits, and rules. An agent posting to the fediverse is really posting to a specific server that then federates the post outward.
SocialHandoff publishes to Mastodon servers and to Threads. See the research labs use case and scheduling for Mastodon.