Introduction to the Fediverse

Social Time

Article from Issue 269/2023

Do you have to you give up your privacy to enjoy access to social media? The makers of the Fediverse say no.

As this magazine goes to press, Twitter has just announced that it is closing its API – a radical move that will limit access from outside applications. Some form of API access might be possible, if you pay for it, but as of now, the terms are unclear, and anyway, the move is likely to cause still more restlessness from the Linux community, who have never had much patience for closed APIs and are likely to abandon the platform in even greater numbers. Where will they go?

Social networking and the new generation of users who live on it have changed the Internet. Your thoughts, your experiences, your pictures, your politics – it all goes on the Internet now through your platform of choice: Life events on Facebook; links and short opinions on Twitter; videos on YouTube; photos on Instagram. The whole world is connected, but many users, including many who have never heard of Linux or free software, have already begun to ask whether it is all worth the price.

"What do you mean," the companies tell us. "Our services are all free." But it all depends on what you mean by free. Commercial social media services earn billions selling knowledge of their users' opinions and habits. To get on the site, you need to click a box that signs away your privacy and, in some cases, even signs away your ownership of your own words and images.

The whole concept of commercial social media as it is practiced today is decidedly at odds with the values of the Free Software community. Former Free Software Foundation attorney Eben Moglen once referred to social media giant Facebook as a "man-in-the-middle attack," adding. "The point is that by sharing with our actual friends through a web intermediary who can store and mine everything, we harm people by destroying their privacy for them. It's not the sharing that's bad, it's the technological design of giving it all to someone in the middle. That is at once outstandingly stupid and overwhelmingly dangerous." [1]

But over the past several years, while the social media giants were erecting their billion dollar empires, another construction project was quietly underway. Now, with recent controversies at Twitter and growing distrust for Facebook, the work of these Free Software pioneers has made a grand entrance onto the scene. Today a new group of tools threatens to upend the social media orthodoxy. Welcome to the Fediverse [2].

Free Speech with Free Tools

The Fediverse is a collection of servers running social media tools that offer access in a decentralized format without the spying. There is no central authority wielding power over the whole system. Servers operate independently, setting their own rules and managing the services as they see fit. The Fediverse is built on the philosophy that tools should work together, so if you have an account on one, you can view content from the others. In other words, you have an account on one server but an identity across the whole federated network. As you will learn in this article, this goal of interoperability has been largely successful, although a few links are still needed to complete the chain.

This month you'll learn about some leading tools of the Fediverse, including:

  • Mastodon – a microblogging platform that lets you send links and short messages (like Twitter)
  • diaspora* – a macroblogging tool, like Facebook
  • PixelFed – a photosharing tool, similar to Instagram
  • PeerTube – a YouTube-like tool for sharing videos

Tools such as Mastodon and diaspora* are receiving a majority of the attention now, perhaps because they fit so neatly into the niches of the conventional platforms they replace, but, as is often the case with Free Software, users have an abundance of choice. Other tools of the Fediverse [3] include:

  • Misskey – a microblogging tool with some extra features, such as a calendar, a chat service, and animated text
  • Hubzilla – a multi-purpose macroblogging platform that calls itself a "home for nomads and power users"
  • Pleroma – a microblogging service tailored for low-resource systems like Raspberry Pi
  • Friendica – an early social media platform that supports multiple protocols for strong connectivity with other Fediverse utilities
  • Funkwhale – a music-sharing platform that also supports "socializing around music and discovering new content"
  • GNU Social – the GNU project's entry into the search for an alternative microblogging platform

The popularity of the Fediverse tools varies widely. Mastodon (Figure 1) is thought to have more than 6 million accounts and 4 million active users. The smallest platforms might have only a couple thousand accounts. But new attention on the Fediverse could accelerate migration in the years to come.

Figure 1: Mastodon is the most popular Fediverse platform, and its popularity is growing with the recent changes at Twitter.

It is worth noting that the concept of federated servers used with the Fediverse is only one approach to the goal of decentralized social media (see the box entitled "Nostr: Even More Decentralized").

Nostr: Even More Decentralized

The tools of the Fediverse don't have a single point of control like Facebook or Twitter, but you still have to set up an account on a server, and whoever owns that server does have some control over the instance of the service you are using. The Nostr protocol [4] provides an approach that is even more decentralized. The goal of Nostr is to provide a "censorship-resistant global social network." Instead of relying on centralized servers in the classic sense, Nostr depends on relays, very simple components that do not participate in the identity management system and do nothing but forward messages. The Nostr GitHub page describes the scenario as follows, "Everybody runs a client. It can be a native client, a web client, etc. To publish something, you write a post, sign it with your key and send it to multiple relays (servers hosted by someone else, or yourself). To get updates from other people, you ask multiple relays if they know anything about these other people. Anyone can run a relay. A relay is very simple and dumb. It does nothing besides accepting posts from some people and forwarding to others. Relays don't have to be trusted. Signatures are verified on the client side." [5]

Tools and Rules

Decentralization is one of the principal features of the Fediverse, and it requires a bit of explanation. A tool such as Mastodon is an open source utility that anyone is free to download and implement. The Mastodon community is not all one single user base. Instead, several different organizations act as Mastodon providers (Figure 2). Each provider makes its own rules and manages its own user base. To get started with Mastodon you can sign up with one of the existing providers, or you can set up a Mastodon server and become a provider yourself. Linux New Media, the publisher of this magazine, has an account with the Mastodon provider called fosstodon. In general, Fediverse providers support interaction with other Fediverse providers, so you aren't locked in to a single garden as you are with many of the commercial social media tools, however, the first step is to set up an account.

Figure 2: Shop for the server that will host your account at the Mastodon website.

This independence of the individual providers means that the Fediverse tools aren't controlled by a single company. On the other hand, this diversity means there is no uniformity in how the providers manage their space and how they envision their mission. A server might serve a specific community of interest or political cause. Whoever owns the server is free to moderate the content as they wish. For instance, the Mastodon server focuses on vegans and offers "anti-speciesist moderation by animal rights activists." On the other hand, Truth Social, the social network created by Donald Trump and supported by users with MAGA political leanings, is also based on Mastodon.


The secret to the interoperability of the Fediverse tools is that they share common protocols. A close look at the supported protocols will give you a better understanding of what fits with what – and which tools might work best for your situation. For historical reasons, or just to improve versatility, some tools support more than one protocol.

The most popular Fediverse communication protocol is ActivityPub. ActivityPub, which is based on the earlier and StatusNet protocols, is a standard of the World Wide Web Consortium. Mastodon, PeerTube, PixelFed, Friendica, and other important Fediverse services use ActivityPub.

Diaspora*, which was developed independently and earlier than many of the ActivityPub applications, has its own protocol that isn't universally compatible with the others, although Friendica and Hubzilla have implemented support for it. One benefit of diaspora* is that it has implemented the necessary extensions to interact with a number of commercial social media services. You can propagate posts to Tumblr and WordPress, and you can even embed YouTube and Vimeo videos in content pages. In the past, diaspora* has had some support for propagating posts to Twitter, but that support might be ending with Twitter closing the API.

GNU Social, another one of the early entries, uses the OStatus protocol, which is also supported by Friendica. Hubzilla, like Friendica, places a premium on interoperability and offers built-in support for both diaspora* and the ActivityPub services. Hubzilla also supports the Zot protocol, which allows it to connect with the Zap macroblogging service.

The differing protocols mean that all the services in the Fediverse aren't exactly federated, in that they can't all directly connect to each other. In general, you can think of the ActivityPub services as one collection and the orbit around the popular diaspora* service as another group (Figure 3). The versatile Friendica and Hubzilla fit into both camps. GNU Social's OStatus protocol is actually a precursor to ActivityPub and at one point offered a degree of compatiblity. Mastodon supported GNU Social until version 3 but has since discontinued it.

Figure 3: ActivityPub is the most common Fediverse protocol, but Diaspora and a few other services use alternatives. Mike Kuketz, CC BY-SA 4.0,

Keep in mind that compatibility among the different services is only part of the equation. In many cases, users are more interested in reaching other users who are within the same tool community. For instance, the Mastodon community is a complete ecosystem where millions of users interact every day – they don't measure their value strictly on the ability to reach other services. The Mastodon community is a federation all by itself, with many servers acting independently yet offering compatibility. Their mission isn't just to offer a backdoor to reach Twitter. They would rather have Twitter users give up their Twitter accounts and come join Mastodon.

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