Bluesky and Mastodon users are having a fight that could shape the next generation of social media

People on Bluesky and Mastodon are fighting over how to bridge the two decentralized social networks, and whether there should even be a bridge at all. Behind the snarky GitHub comments, these coding conflicts aren’t frivolous — in fact, they could shape the future of the internet.

Mastodon is the most established decentralized social app to date. Last year, Mastodon ballooned in size as people sought an alternative to Elon Musk’s Twitter, and now stands at 8.7 million users. Then Bluesky opened to the general public last week, adding 1.5 million users in a few days and bringing its total to 4.8 million users.

Bluesky is on the verge of federating its AT Protocol, meaning that anyone will be able to set up a server and make their own social network using the open source software; each individual server will be able to communicate with the others, requiring a user to have just one account across all the different social networks on the protocol. But Mastodon uses a different protocol called ActivityPub, meaning that Bluesky and Mastodon users cannot natively interact.

Turns out, some Mastodon users like it that way.

Software developer Ryan Barrett found this out the hard way when he set out to connect the AT Protocol and ActivityPub with a bridge called Bridgy Fed.

The conflict harks back to blogging culture in the early 2000s, when people worried about their innermost thoughts and feelings being indexed on Google. These bloggers wanted their posts to be public, so that they could try to form communities with like-minded people on platforms like LiveJournal, but they didn’t want their intimate musings to accidentally fall into the wrong hands.

Barrett has no affiliation with Mastodon or Bluesky, but since the protocols are open source, any third-party developer can build on the existing code. As Bluesky federation draws nearer, some Mastodon users caught wind of Barrett’s project and lashed out.

Barrett planned to make the bridge opt-out by default, meaning that public Mastodon posts could show up on Bluesky without the author knowing, and vice versa. In what one Bluesky user called “the funniest github issue page i have ever seen,” there was a heated debate over the opt-out default, which — like any good internet argument — included unfounded legal threats and devolved into bizarre personal attacks.

Barrett has worked on projects like Bridgy for the last 12 years, yet he’s never experienced quite such an intense reaction to his work.

“It hasn’t been easy the last couple of days, being the main character of the fediverse,” Barrett told TechCrunch. But he’s sympathetic to the fear that some Mastodon users have about their posts showing up in places they didn’t anticipate.

“A lot of the people there, especially people who have been there for a while, came from more traditional centralized social networks and got mistreated and abused there, so they came looking for and tried to put together a space that was safer, smaller and more controlled,” Barrett said. “They expect consent for anything they do with their data.”

A common misconception about the bridge is that it would immediately integrate Bluesky and Mastodon entirely. But that’s not how the technology works.

“Some people have assumed that when the bridge goes live, immediately every fediverse post will be visible on Bluesky, and vice versa, and the bridge proactively takes them and shoves them in across in both directions,” Barrett said. “It only does that when someone first requests to follow a person across the bridge.”

With the help of constructive feedback from the GitHub discussion, Barrett decided to build what he calls a “discoverable opt-in.” That way, users on either side of the bridge have to request to follow accounts from across the bridge, and then that user will get a one-time pop-up asking if they want their accounts to be bridged across the two networks or not.

Already, the most ardent Mastodon and Bluesky evangelists are finding themselves acting like rival factions in a war for the open web. But as decentralized social networks become more popular, the way that these ecosystems on different protocols interact with one another could set the stage for the next era of the internet.

Mastodon adherents have been skeptical of Bluesky from the get-go. As a nonprofit, Mastodon’s appeal is that, unlike Instagram or Twitter or YouTube, it’s not controlled by a big corporation that needs to make its investors happy. But in its earliest stages, Bluesky was a project at Twitter, funded by Twitter co-founder and former CEO Jack Dorsey. Bluesky is now its own company, completely separate from Twitter. Even though Dorsey sits on its board, he has proven far more interested in Nostr, another decentralized protocol he backed.

For anti-establishment Mastodonians, Dorsey’s involvement was strike one. Strike two came when Bluesky decided to create its own protocol instead of using an existing one, like ActivityPub. Now, the debate over Bridgy Fed is something like a foul tip ahead of strike three.

The prevailing culture is different between Mastodon and Bluesky, with Mastodon trending more serious and Bluesky more cheeky. Some of these differences come from the leaders of the platforms themselves.

“The whole philosophy has been that this needs to have a good UX and be a good experience,” Bluesky CEO Jay Graber said on a panel last month. “People aren’t just in it for the decentralization and abstract ideas. They’re in it for having fun and having a good time here.”

On the other hand, Mastodon adoptees often join the platform because they believe in its technology. And sometimes, they believe in it so strongly that they take offense to Bluesky (the company) building a whole other protocol from scratch, rather than integrating with ActivityPub. Even ActivityPub co-author Evan Prodromou has expressed his distaste for Bluesky.

“The best thing that [Bluesky] can do for its users is implement ActivityPub to connect to the millions of users on the fediverse,” Prodromou wrote on Instagram’s Threads, which plans to support some form of interoperability with ActivityPub.

The ideological issues around Bridgy Fed are likely to continue stoking tension across these federated social networks as they increase their connection points. Soon, Meta’s Threads app plans to become interoperable with ActivityPub networks like Mastodon. Flipboard and Automattic, owner of WordPress.com and Tumblr, are also betting on ActivityPub. For Mastodon users who want to remain isolated from traditional social networks, these connections to other platforms — particularly Threads, which has 130 million active users — could pose a greater threat than a third-party Bluesky bridge.

For now, Barrett is still working on Bridgy Fed so that it will be ready to go when Bluesky federates. If anything, his brief stint as the “main character of the fediverse” reinforced his focus on safety.

“I am thinking and feeling deeply that however content moderation works on either side of the bridge, it needs to be at least as good as it is for native fediverse users, and vice versa,” Barrett said. “I am on the hook if I put this out here.”