The Fediverse and Mastodon Explained

The fediverse is a network of independently run social media servers that can talk to each other, much like email providers do. Mastodon is the best-known software for running one of those servers. If you sign up on one Mastodon server, you can follow, reply to and message people on thousands of others, without any single company owning the whole network.

The word comes from "federation" plus "universe". The servers in it don't all run the same app, but they share a common language for exchanging posts.

The email comparison

The simplest way to understand the fediverse is to think about email. Someone with a Gmail address can write to someone with an Outlook address, because both providers follow the same standards. No company controls email as a whole, and you can choose a provider you trust.

The fediverse works the same way. Your address looks like @name@server.example, where the second part is the server that hosts your account. Your server stores your posts and passes them to the servers of people who follow you.

The shared language is ActivityPub, a standard published by the World Wide Web Consortium (W3C) in January 2018. Mastodon uses it, and so do many other programs: Pixelfed for photos, PeerTube for video, Lemmy for link-sharing communities, and others. A Mastodon user can follow a Pixelfed account and see its photos in their timeline. Meta's Threads also has an optional fediverse sharing setting, which lets Threads posts reach Mastodon users.

How Mastodon feels day to day

Mastodon looks familiar if you've used X: short posts (500 characters by default, though some servers allow more), replies, boosts instead of reposts, favorites, hashtags and lists.

A few things work differently. Your home timeline shows posts from accounts you follow, in the order they were posted, with no ranking algorithm deciding what you see. There's also a local timeline with public posts from your own server, and a federated timeline with public posts from servers yours knows about. Content warnings are widely used to fold away spoilers or difficult subjects. Quote posts only arrived in late 2025, after years of debate about pile-ons, and they come with a setting that controls who may quote you.

Search is deliberately limited. On many servers you can search hashtags and accounts, and full-text search only covers posts whose authors have allowed it. That's a privacy choice, and it's one of the reasons Mastodon feels quieter.

Choosing a server

This is the step that puts many people off, but it matters less than it seems, because you can talk to people on nearly every other server and you can move later.

Before you join, look at the server's About page to see who runs it and how it's paid for. A server run by a team, a nonprofit or a company with clear funding is less likely to vanish overnight than one run by a single volunteer. Read the rules, too, since every server sets its own and they say a lot about the kind of place it is.

Size changes the feel. Big general servers such as mastodon.social are easy to start on, while smaller servers for a city, a profession or a hobby often have a friendlier local timeline. Finally, check the server's reputation. Servers can block other servers, which is called defederation, and one that is widely blocked for ignoring abuse will cut you off from much of the network.

Avoid treating any server as permanent until you've used it for a few weeks.

Moving to another server

Mastodon's account move feature lets you set up an account on a new server, point your old account at it, and have your followers moved across automatically on servers that support it. The list of accounts you follow, plus your blocks, mutes and lists, can be exported as files and imported on the new server.

Your posts don't move. Mastodon's own documentation is clear that this is a technical limitation. You can download an archive of your posts and media before you go, and the old profile shows a notice pointing to the new one. After a move, you have to wait 30 days before moving again.

Our guide on leaving a platform without losing your network covers moves between networks too.

What's private and what isn't

Mastodon has some real privacy advantages. There are no ads, no ad tracking and no engagement algorithm learning from your behavior. Many servers keep very little data about you beyond your email address and login records.

But a few points surprise new users:

• Public posts spread. When you post publicly, copies go to every server where someone follows you, and public posts can travel further through boosts. If you delete a post, Mastodon sends a deletion request to those servers, but a badly behaved server can ignore it.
• Your admin can see your account. The people who run your server can see your email address, your IP addresses and, technically, your private posts. Choose a server run by people you're comfortable trusting.
• Private mentions aren't encrypted. Direct messages on Mastodon, now called private mentions, are posts with restricted visibility. They aren't end-to-end encrypted, and admins on both your server and the recipient's can read them. Use an encrypted messenger for anything sensitive. See safer DMs and group chats.
• Follower lists can be public. You can hide who you follow and who follows you in your profile settings.

You can also require approval for new followers, keep posts out of search results, and choose per post whether it's public, quiet public (it won't show in public timelines or search), followers-only or a private mention. The privacy checker lists the Mastodon settings worth reviewing.

Is it worth trying?

Mastodon suits people who want a calmer, chronological feed and are comfortable with a bit of setup. It's less good for building a large audience fast, since there's no algorithm pushing posts to strangers. Many people keep an account on a mainstream app and one in the fediverse, then let their habits decide which one they keep opening.

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