Germ launches first native encrypted messenger on Bluesky

Germ has become the first private messenger that can be launched natively within the Bluesky app. Following the official integration announcement earlier this month, the startup’s daily active users jumped by 5x, according to the Germ team. Prior to the integration, Germ’s standalone app had seen thousands of downloads during its public beta, which launched in August and remains available on iOS in North America and Europe.

California-based Germ was founded by CEO Tessa Brown, a communications scholar, and CTO Mark Xue, a former Apple privacy engineer. The startup utilizes Messaging Layer Security (MLS), an encryption standard approved by the Internet Engineering Task Force (IETF), alongside the AT Protocol—the decentralized social protocol powering Bluesky. Instead of requiring phone numbers, Germ integrates with the AT Protocol to enable encrypted chats, meaning messages cannot be decrypted by Bluesky or Germ itself. To message a user, a friend clicks the Germ badge on a Bluesky profile, which launches an iOS App Clip—a lightweight, temporary app experience. Users authenticate with their AT Protocol handle to send messages immediately, with an optional nudge to download the full standalone app.

The startup has been coordinating with the developer community since the ATmosphere Conference in Seattle last year. Germ previously launched a private beta in August using shared links in user bios. Xue noted that shipping the August beta generated valuable feedback from users and developers who wanted to replace bio links with a native user interface. While the AT Protocol could eventually implement E2E encryption, Bluesky is not currently focusing on designing an encryption system itself. Daniel Holms, a protocol engineer at Bluesky, explained: “The reality is that E2EE is hard. And this inherent complexity isn’t something that the protocol team at Bluesky can just handle – it gets pushed out to every dev trying to build a client that works with encrypted data”

Following the integration, which was led on the Bluesky side by head of product Alex Benzer, other ecosystem players have adopted the tool. Blacksky, another AT Protocol-based client, has already added support for the Germ badge. While Germ is currently focused on shipping everyday messaging features, Brown noted that the company may test paid features in the future, potentially targeting power users such as creators, journalists, and politicians.

Why it matters

The integration of Germ into Bluesky marks the first time a private messenger has launched natively within the app, highlighting how open social networking ecosystems allow for community-developed functionality rather than relying solely on the platform company.