Bluesky is a social app that is designed to not be controlled by a single company. We’re creating a version of social media where it's built by many people, and it still comes together as a cohesive, easy-to-use experience. We've done this by building Bluesky on the AT Protocol, an open source toolbox for building social apps that can all talk to each other.
We want modern social media and public conversation online to work more like the early days of the web, when anyone could put up a blog or use RSS to subscribe to several blogs. We believe this will unlock a new era of experimentation and innovation in social media. Researchers and communities will have the ability to jump in to help solve the problems social networks currently face, and developers will be able to experiment with many new forms of interaction.
Traditional social networks are often closed platforms with a central authority. There’s a small group of people who control those companies, and they have total control over how users can use the platform and what developers can build. On these platforms, as a user, if you try to leave, you have to start over from scratch without the connections you built there or the content you made. As a developer, if you try to build a new app, you have to overcome network effects to rebuild the social graph from scratch, and if you try to build on the APIs of these companies they can cut you off and kill your company in the blink of an eye. As a creator, you might spend years building an audience only to lose access to it when the platform changes the rules on you.
The AT Protocol is a protocol for public conversation and an open-source framework for building social apps, meaning people have transparency into how it is built and what is being developed. It creates a standard format for user identity, follows, and data on social apps, allowing apps to interoperate and users to move across them freely. It is a federated network with account portability.
An analogy to explain this: every time you create an account on a social platform, it’s like moving to a new city. You make friends and create posts, which is like filling your house with furniture you made. But on centralized social platforms, if you leave, it's like leaving all your friends behind with no way to contact them, and leaving your house behind without being able to take anything with you. Leaving a centralized site and starting over from scratch is very hard.
The AT Protocol essentially lets people move between cities. Creating a standard format for identity and data is like giving people a passport, cell phone, and property rights. If you don’t like the city you first moved to, you can relocate and take all your belongings (data) with you. Your friends will still be able to find and stay in touch with you at the same name and number (identity & follow graph).
The AT Protocol offers account portability, as well as algorithmic choice and composable moderation, which you can read more about in the linked blog posts.
Mastodon is another federated social network built on a protocol called ActivityPub. While Bluesky — built on AT Protocol — shares the term “federation” with other networks, the way it works is very different.
On Bluesky, server choice doesn’t affect what content you see. Servers are only one piece of the protocol — when you browse Bluesky, you see posts that are pulled together from many different servers. This is why you can change your server after signing up without losing your username, friends, or posts.
A summary of some ways Bluesky differs from Mastodon:
A focus on the global conversation: On Mastodon, your “instance”, or server, determines your community, so your experience depends on which server you join. An instance can send and receive posts from other instances, but it doesn’t try to offer a global view of the network. Your Mastodon server is part of your username, and becomes part of your identity. On Bluesky, your experience is based on what feeds and accounts you follow, and you can always participate in the global conversation (e.g. breaking news, viral posts, and algorithmic feeds). You can use your own domain name as your username, and continue participating from anywhere your account is hosted.
Composable moderation: Moderation on Bluesky is not tied to your server, like it is on Mastodon. Defederation, a way of addressing moderation issues in Mastodon by disconnecting servers, is not as relevant on Bluesky because there are other layers to the system. Server operators can set rules for what content they will host, but tools like blocklists and moderation services are what help communities self-organize around moderation preferences. We’ve already integrated block and mute lists, and the tooling for independent moderation services is coming soon.
Composable feeds: We designed your timeline on Bluesky so that it’s not tied to your server. Anyone can build a feed, and there are currently over 40,000 algorithmic feeds to choose from. Your Mastodon timeline is only made up of posts from accounts you follow, and does not pull together posts from the whole network like Bluesky’s custom feeds.
Account portability: We designed federated hosting on Bluesky so that you can move servers easily. Moving hosting services should be like changing your cell phone provider — you should be able to keep your identity and data. Changing servers on Bluesky doesn’t disrupt your username, friends, or posts.
Bluesky Social, the company, is a Public Benefit Corporation. It is owned by Jay Graber and the Bluesky team. The board consists of Jay Graber; Jeremie Miller, the inventor of Jabber/XMPP; Mike Masnick; and Kinjal Shah. Find past public statements we have made about Bluesky Social PBC's governance and structure in our original announcement, other posts on our blog, and on social media.
Bluesky was initially a project kicked off by Jack Dorsey when he was CEO of Twitter in 2019. Jack chose Jay to lead Bluesky, and Twitter paid Bluesky services income to build an open social protocol for public conversation that it could someday become a client on. Bluesky has been an independent company since its formation in 2021.
In late 2022, Twitter chose to sever the service agreement with Bluesky, and Bluesky agreed. The Bluesky Social PBC has continued to pursue its original founding mission to “develop and drive large-scale adoption of technologies for open and decentralized public conversation.”
As of January 2025, Bluesky has over 30 million users.
Sign up for Bluesky at bsky.app. (No invites required!)
Our approach to moderation is three-fold: automated filtering, manual admin actions, and community labeling. It stacks new approaches to moderation on top of what centralized social sites already do, and exposes the internals of the system for anyone to observe.
The open and composable labeling system for moderation we’re creating will allow anyone to define and apply labels to content or accounts, and lets anyone choose to subscribe to these label sets. Labels can be automatically or manually generated, and can be applied by any service or person in the network.
For more information, read our original blog post on composable moderation.
For FAQ about the AT Protocol, please visit here.
For media inquiries, please contact press@blueskyweb.xyz.
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Bluesky is a microblogging social media service. Users can share short posts containing text, images, and videos. It is owned by Bluesky Social PBC, a benefit corporation based in the United States.
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Bluesky was developed as a reference implementation of the AT Protocol, an open communication protocol for distributed social networks. Bluesky Social promotes a composable user experience and algorithmic choice as core features of Bluesky. The platform offers a "marketplace of algorithms" where users can choose or create algorithmic feeds, user-managed moderation and labelling services, and user-made "starter packs" that allow users to quickly follow a large number of related accounts within a community or subculture. The AT Protocol offers a domain-name–based handle system within Bluesky, allowing users to self-verify an account's legitimacy and identity by proving ownership of a domain name.
Bluesky began in 2019 as a research initiative at Twitter, becoming an independent company in 2021. Development for the social app accelerated in 2022 after Elon Musk's acquisition of Twitter and subsequent severing of ties between the companies. Bluesky launched as an invite-only service in February 2023 and opened registrations in February 2024. Former Twitter CEO Jack Dorsey left Bluesky Social's board by May 2024. The social media platform grew after October 2024, reaching 20 million users by November 2024 and 30 million by January 2025.
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