What is the Mastodon documentation site?

docs.joinmastodon.org is the official documentation site for the Mastodon software. It is a reference site, not a Mastodon server: you cannot sign up, post, or follow anyone there. Use it when you want to understand how Mastodon works, how federation and ActivityPub fit together, or how to run and use a Mastodon server.

What the site covers

The documentation is organized around explaining Mastodon as software rather than promoting a particular server. Its opening section, "What is Mastodon?", walks through the core concepts:

• Microblogging — publishing small updates to a stream on your profile, with optional media such as pictures, audio, video, or polls.
• Federation — a form of decentralization where many independent services interoperate instead of one central service serving everyone.
• ActivityPub — the standardized, open protocol Mastodon uses to implement federation.

The site places these in context with a comparison of network structures:

The email analogy is the one the documentation leans on: just as you can send mail from Gmail to Outlook, Fastmail, or Protonmail, a Mastodon user can mention or message anyone on any participating website using their address.

Why the ActivityPub explanation matters

Mastodon is not the only software speaking ActivityPub. The documentation names several other implementations that can communicate with Mastodon servers:

• Pleroma — a modular microblogging engine
• Pixelfed — federated image sharing
• Misskey — microblogging plus a customizable dashboard
• PeerTube — video uploads to channels
• Plume — longer-form articles

Together these form the fediverse, the set of websites that can communicate over ActivityPub and the web. The documentation notes that "follow me on Mastodon" is more common than "follow me on the fediverse," even though the latter is technically more accurate.

Practical implications it raises

Because Mastodon is software that can power any website, the documentation points out that service provider and policy choices matter — the server you join sets rules you are subject to. It also includes a "Choose your path" section, which separates readers who want to use Mastodon from those who want to run a server.

When to use this site

Reach for docs.joinmastodon.org when you need:

• A definition of federation, ActivityPub, or the fediverse
• Guidance on running or administering a Mastodon instance
• An explanation of how Mastodon differs from centralized platforms

Skip it if you are looking for a server to join or an account to create — that happens on an individual Mastodon website, not on the documentation site.