A startup called Germ becomes the first private messenger launched directly from the Bluesky app.

This is something we have never seen on Big Tech social platforms. Decentralized open social network Bluesky has integrated a new technology from a startup called Germ Network to bring end-to-end encrypted (E2E) messaging to the Bluesky app. This move makes Germ DM the first private messenger that can be launched natively within the Bluesky app.

Along with this release, Germ is also releasing new guidance to enable other apps built on Bluesky’s underlying AT protocol to do the same.

This move is a notable example of how open social networking ecosystems work differently than the Big Tech platforms that dominate the space today, as new features and functionality can be developed by communities, not just companies themselves.

Bluesky announced its integration with Germ earlier this month, noting that the experimental integration will allow Germ users to add a button to their profile, allowing others to send messages on Bluesky in an E2E encrypted environment.

Meanwhile, Germ’s standalone app is also available in public beta on iOS in North America and Europe. The app had previously been downloaded thousands of times, but after the official integration announcement, the number of daily active users jumped five times, the team said.

California-based Germ is a startup founded by Tessa Brown, a communications scholar who taught at Stanford University, and Mark Xue, a privacy engineer at Apple who worked on technologies such as FaceTime and iMessage. The idea, the company previously explained to TechCrunch, was to provide an alternative to other E2E encryption platforms like iMessage, Signal, and WhatsApp, built on new technology.

Germ now leverages Messaging Layer Security (MLS), a new standard approved by the Internet Engineering Task Force (IETF), and AT Protocol (or ATProto), which powers Bluesky, Skylight, and a growing number of other social apps.

Instead of asking for a user’s phone number, Germ integrates with ATProto to enable encrypted chats. This means that Germ messages cannot be decrypted by Germ itself or by other services, including Bluesky.

To use the new Messenger, simply click the badge on your friend’s profile on Bluesky, which will open an iOS App Clip (a lightweight temporary app). Click Open in this app experience and authenticate by logging in with your ATProto handle. You can instantly send messages to your friends. You will also be prompted to download the full Germ DM app, but this is optional.

If you want to add a badge to your profile, download the Germ DM app on iOS and authenticate your Bluesky credentials there. (Note: I had to force close and restart the Bluesky iOS app before the Germ badge appeared.)

The company has been building the official Bluesky integration for months, starting with a private beta in August that started with a “magic link” shared in users’ bios. From now on, users who set up Germ to work within Bluesky will receive a new badge displayed on their profile and will be able to remove the in-profile link option they previously used. (Links still work, but badges are easier to use and, of course, more noticeable.)

Germ told TechCrunch that his startup has been in dialogue with the ATProto developer community, including Bluesky’s app and protocol teams, since last year’s ATmosphere Conference in Seattle.

“We have been transparent about our plans and roadmap, and once we shipped the private beta in August, we received valuable feedback from users and developers who wanted to replace links in the BIOS with a native UI,” said Xue, CTO at Germ Network. “Both our team and the team at Bluesky saw value in improving AppView support for Germ links.”

Changes to the Bluesky app were led by product director Alex Benzer as the company looked to experiment with implementing third-party services within Bluesky.

“I really enjoyed working directly with the Bluesky team,” Germ CEO Brown told TechCrunch. “They ship quickly, prioritize user experience, and care about users’ access to end-to-end encrypted messaging. We’re excited to be the first secure messenger they bring natively into their app.”

While it is true that the AT protocol may eventually implement E2E encryption, that is not the focus today. As Bluesky protocol engineer Daniel Holms recently explained, the company has several reasons for not designing the system itself.

“The reality is that E2EE is difficult,” he wrote in a blog post. “And this inherent complexity isn’t something Bluesky’s protocol team can handle alone; it’s pushed onto any developer looking to build a client that works with encrypted data,” Holmes says.

Xue agreed, adding, “We share ATProto’s philosophy that people should be able to communicate using the apps and tools of their choice. We believe ATProto users will continue to choose us because we solve their toughest problems in a secure, transparent, and user-friendly manner.”

Shortly after Bluesky added support for Germ badges, another AT protocol-based client, Blacksky, added support as well.

Brown said the team is currently focused on providing more day-to-day messaging capabilities rather than monetization. However, further down the line, Germ may test paid features.

“We expect our first paid features to be centered around the needs of prosumer power users such as creators, journalists, and politicians, such as support for multiple handles and private AI screening of the first message from a new connection,” she said.