Germ Brings End-to-End Encryption to Bluesky

Germ Introduces Encrypted Messaging for Bluesky

A new company, Germ, is implementing end-to-end encrypted messaging for the Bluesky social network. This provides users with a more secure communication alternative to Bluesky’s standard direct messages.

After more than two years in development, the service is initiating its beta phase this week for encrypted DMs on Bluesky. A gradual rollout to new testers is planned before a full public release.

Leveraging New Technologies

The technology developed by Germ, a significant portion of which is open-sourced, has the potential to enable Bluesky to integrate encrypted messaging directly into its own application.

Germ was created as a different option to established end-to-end encrypted platforms such as iMessage, Signal, and WhatsApp. It utilizes modern technologies, including Messaging Layer Security (MLS) – a new standard ratified by the Internet Engineering Task Force (IETF) – and the AT Protocol (ATProto), which underpins Bluesky.

Unlike some messaging applications that require a phone number, Germ integrates with ATProto. This allows users to securely communicate with contacts on Bluesky and across the wider open social web, including platforms like Flashes and Skylight, while maintaining greater control over their experience.

User Control and Privacy Features

Users can customize their DM settings, choosing to accept messages only from those they follow on Bluesky. Alternatively, they can restrict message initiation to themselves. Furthermore, blocking a user in Germ offers the option to block them across Bluesky and other ATProto-based apps.

The Team Behind Germ

Germ was founded by Tessa Brown, CEO, a communications scholar formerly at Stanford, and Mark Xue, a privacy engineer previously at Apple, where he contributed to technologies like FaceTime and iMessage.

Brown’s research highlighted the importance of private communication for healthy social networks.

“Psychologically, strong relationships are difficult to cultivate when individuals feel constantly observed and manipulated,” explains Brown to TechCrunch. “Social media often fosters this environment. My work reinforced my belief in end-to-end encrypted messaging as a cornerstone of the future of social media and communication.”

Xue, drawing from his experience at Apple, believed that reliance on phone numbers for secure communication is an outdated approach and sought to develop a novel solution.

How Germ Works: The "Magic Link"

Currently, Germ operates through a “magic link” generated for each user and placed in their Bluesky bio. When another Bluesky user on iOS clicks this link, they can begin a chat immediately without needing to download a separate application.

This functionality is enabled by Apple’s App Clips, a feature allowing users to experience a portion of an app’s functionality without a full installation. App Clips are typically used for simple transactions, such as paying for parking via QR code, but Germ repurposes them for instant messaging.

The link itself functions as a cryptographic key, verifying the user’s ATProto identity and confirming their association with the corresponding Bluesky handle.

From the Germ App Clip, users have the option to install the full Germ iOS app, which provides enhanced controls, access to a friends list, and Bluesky pairing capabilities.

While the pairing process experienced some issues during testing, potentially due to running the iOS 26 developer beta, a workaround involved initiating the chat from the App Clip first.

Future Prospects and Community Integration

Brown expressed enthusiasm for building within the Bluesky community, noting its increasing influence and the participation of prominent figures in U.S. politics, including Barack Obama, Hillary Clinton, and various representatives, senators, and governors.

Given Germ’s advancements in encrypted messaging technology, Brown is optimistic that its protocol could be widely adopted by Bluesky and other platforms.

While currently available without charge, Germ may introduce a premium subscription in the future, offering advanced features like private AI services and personalization options.

The four-person startup has secured pre-seed funding from angel investors, including an MLS co-author and other trust and safety specialists. Institutional investors include K5 Global and Mozilla Ventures. The company intends to seek further funding to develop an Android version.