Fediverse

The Fediverse is an association of many small social networks. Each of these runs on its own computer on the internet, operated by a company, an association, or a private individual. Yet these networks are not cut off from one another: they send each other posts, replies, and likes. So anyone with an account on one of these servers can follow people on all other servers. The name is made up of the English words for federation and universe. The closest comparison is with email: there too, it doesn’t matter whether someone has an address at Gmail or at a university server, the message still arrives.

A social network without a single owner

Large platforms like Instagram or X each belong to a single company. That company alone decides which posts are visible, what rules apply, and how much advertising is shown. If it changes its rules, users are left with only the choice between going along with it or leaving. Anyone who leaves loses all their contacts.

In the Fediverse, this power is distributed among thousands of operators. If someone no longer likes how their server is run, they can move to another one. They take the list of accounts they follow with them. This is called data portability, meaning the ability to take one’s own data along.

This has since become a political topic. The EU has been debating for years whether large platforms have become too powerful. Many see the Fediverse as a practical counter-model. Since 2022, the EU Commission has itself been running its own server on the Fediverse.

How the servers talk to each other

For different programs to understand each other, they need a common language. This language is called ActivityPub and is an open standard, meaning a set of rules freely accessible to everyone. It defines how a message must be structured so that every server can read it. The technical term for such a shared set of rules is protocol.

An example: you follow an account on another server from your own server. Your server registers a subscription there. From then on, the other server automatically sends every new post to your server. Your server stores a copy and displays it to you. This process is called federation.

Each server has its own rules and its own moderators. It can completely block other servers, for instance if hate speech is spread there. This is both a strength and a weakness. Because a poorly maintained server can be shut down at any time, and then the posts there are gone.

Mastodon, Pixelfed, and the Threads connection

The best-known service in the Fediverse is Mastodon, an alternative to X with short text posts. After Elon Musk’s takeover of Twitter in late 2022, it grew strongly, but still has only about one million active users per month. There is also Pixelfed for photos and PeerTube for videos. All three speak the same language and are therefore connected to one another.

Since 2024, Meta's Threads has also been partially linked to the Fediverse. This allows Mastodon users to follow Threads accounts. Whether a corporation with hundreds of millions of users strengthens or crushes a network of small servers is hotly debated in the tech press.

A common misconception: the Fediverse is not an app and not a company. You cannot sign up “for the Fediverse.” You always choose a specific server, and the address then looks similar to an email address.