What is the fediverse?
The fediverse is a collection of independently hosted interconnected servers. The term is a portmanteau of the words federated and universe. In social networking, the fediverse refers to a collection of independent social applications linked by a common protocol.
In computing, federated refers to a group of independent entities that are united under a central organization. Federated identity management is one example, in which users log in to multiple independent applications using a single set of credentials.
What is the fediverse used for?
Fediverse servers are used for web publishing, file hosting, blogging and social networking. Users create identities on different servers and communicate across servers using open standard network protocols.
The fediverse is decentralized, meaning each server instance is independent -- there is no central authority that controls the instances in the fediverse. An instance is a physical server or virtual machine that runs an application.
The fediverse shares data among multiple social media applications, creating a more efficient user experience when moving among them. This example works similarly to email. There are many email applications -- including Gmail, Yahoo and Hotmail -- and they can communicate using a common standard protocol.
Communication protocols used in the fediverse
One of the most used protocols for social networking in the fediverse is the ActivityPub protocol. It is a decentralized social networking protocol developed by the World Wide Web Consortium (W3C). It is based on the ActivityStreams 2.0 data format.
ActivityPub provides a client-to-server application programming interface for updating, creating and deleting content, and a server-to-server API for delivering notifications and content. It is used in many social networking platforms, including Mastodon, and as a plugin for WordPress.
Another commonly used protocol is OStatus. OStatus is a protocol for distributed status updates and microblogging. Mastodon used OStatus until October 2019.
OStatus and ActivityPub aren't the only protocols. Some others include the following:
Examples of fediverse platforms
Meta Threads plans to be a fediverse platform. Threads was released in July 2023 and gained a million followers in just over a week. Threads announced plans to build in support for ActivityPub and join the fediverse.
Mastodon is another platform in the fediverse. Mastodon is a Twitter clone based on the Ruby programming language, and it also uses ActivityPub. Users publish links, pictures, text and video on the community-owned, ad-free platform.
Aside from the above two examples, other platforms are participating in the fediverse too, including the following:
- Pixelfed. A free photo-sharing platform like Instagram.
- PeerTube. A decentralized video hosting network like YouTube.
- Lemmy. A link aggregator like Reddit.
- Movim. A decentralized social network.
- Prismo. A federated link aggregator like Reddit.
- Pleroma. A microblogging service like Twitter. Based on the Elixir programming language.
- Diaspora. A federated Facebook clone. Based on the Ruby programming language.
- Kbin. A federated content aggregator and microblogging platform.
- Friendica. A decentralized social platform like Facebook.
- WriteFreely. A publishing platform based on the Go programming language.
In addition to Threads, some older well-known platforms have built-in support for the fediverse via plugins. Drupal is an open source content management system with ActivityPub support. Another example is the Open Source content management system WordPress.
Benefits of the fediverse
The main benefit of the fediverse is decentralization. The fediverse separates the user interface from the underlying data.
A Twitter account's followers and posts exist on Twitter's servers. A Facebook or Instagram account's data exists on Meta's servers. They are not interoperable -- follower lists can't be transported between servers.
A fediverse application's data exists on an independent server instance and can travel between applications. If a user doesn't want to or can't use a platform for some reason, they can port their data to another application. The fediverse would eliminate platform lock-in.
If a traditional social application's central server goes down, users often experience performance issues. If a particular social media company goes out of business, the users on that platform lose their following and posts. The fediverse ensures one service provider's issues don't disproportionately affect users. If an application goes down in the fediverse, user data can still exist on other independent servers.
Challenges of the fediverse
One obstacle to ActivityPub and other fediverse protocols scaling up is inconsistent underlying infrastructure. There are dozens of apps that use fediverse protocols, but none are as popular as the big social platforms. A fediverse app such as Mastodon would have trouble taking on the user count that Facebook has all at once because many of the independent servers powering the fediverse operate out of people's homes. As more are added, the fediverse would become more fragile, as each has its own specific maintenance needs.
Having centralized, proprietary servers hold all the data has traditionally been more profitable than the decentralized model. There's little incentive for platforms to adopt the open standard, and little incentive for users to switch to a significantly less popular, less intuitive platform that they are unfamiliar with if the old, familiar platforms still work.
Content moderation is another challenge of the social fediverse. It's difficult to make platform-wide content moderation decisions because of the decentralized nature of fediverse apps. Centralized social platforms such as Facebook, TikTok and Twitter have unifying content moderation policies that prevent hate speech and other disallowed content.
History of the fediverse
The idea of a fediverse has been around for decades -- about as long as the web. At various points, big tech companies embraced the idea. One example is Google Buzz, which supported the OStatus protocol. Protocols such as RSS have long been used to create more open social networking experiences through data feeds.
In 2008, Evan Prodromou founded microblogging platform Identi.ca and published it to an open source server called Gnu Social that used the OStatus protocol. In the years that followed, several more platforms emerged using the OStatus protocol -- Friendica, Diaspora and Pump.io.
In 2016, two notable social networks emerged: Mastodon and Pleroma. Mastodon is a popular Twitter alternative.
In 2018, W3C created the ActivityPub protocol -- with one of the co-editors being Evan Prodromou -- and more platforms emerged, including PeerTube and Pixelfed. Mastodon also switched protocols from OStatus to ActivityPub in 2019.
In 2023, Threads' release sparked new interest in the fediverse and ActivityPub as its go-to protocol. Threads opened up the possibility of a fediverse flagship platform backed by a big tech company with a large user base.