A new startup called Germ is bringing end-to-end encrypted messaging to the Bluesky social network, offering users a more secure option for chats compared to Bluesky’s existing direct messages. After over two years of development, the service is launching its encrypted DMs for Bluesky into beta this week, with plans to gradually onboard new testers before a public release.
The technology Germ is building, much of which is open-source, could eventually allow Bluesky to integrate encrypted messaging into its own app. Germ aims to provide an alternative to dominant end-to-end encrypted platforms like iMessage, Signal, and WhatsApp. It leverages newer technologies such as Messaging Layer Security (MLS), a standard approved by the Internet Engineering Task Force, and the AT Protocol, which powers Bluesky.
Unlike messaging apps that require a phone number, Germ integrates with ATProto, enabling users to securely chat with friends on Bluesky and other apps in the open social web, such as Flashes and Skylight. Users also have added controls over their experience—they can choose to accept DMs only from people they follow or configure settings so that only they can initiate chats. Blocking a user in Germ also allows the option to block them across Bluesky and other ATProto-powered apps.
Germ was co-founded by Tessa Brown, a communications scholar and former Stanford instructor, and Mark Xue, a privacy engineer who worked on technologies like FaceTime and iMessage at Apple. Brown’s research led her to believe private communication is essential for healthy social networks. She explains that social media today often feels invasive, making encrypted messaging a key part of the future of online interaction.
Xue, on the other hand, saw phone numbers and telephony as outdated foundations for secure communication and wanted to create something new. Germ’s service uses a “magic link” generated for users and placed in their Bluesky bio. When another Bluesky user on iOS clicks the link, they can start chatting immediately without downloading the full app, thanks to Apple’s App Clips technology.
The link itself is a cryptographic key that verifies the user’s ATProto identity, ensuring they are the rightful owner of the Bluesky handle. From the App Clip, users can install the full Germ iOS app for additional features, including access to their friends list and Bluesky pairing. Some users have reported minor issues with pairing, possibly due to beta software, but workarounds exist.
Brown is excited about building within the Bluesky community, which has gained cultural traction and attracted notable figures in U.S. politics, including Barack Obama and Hillary Clinton. Since Germ is ahead of Bluesky in developing encrypted messaging, Brown hopes its protocol could be adopted more widely in the future.
Currently free to use, Germ may introduce a premium subscription later, offering advanced services like private AI tools and personalization features. The four-person startup has raised pre-seed funding from angel investors, including an MLS co-author and trust and safety experts, as well as institutional investors like K5 Global and Mozilla Ventures. The company plans to seek additional funding to develop an Android version.