BandarLabs Launches Cobalt to Bring Third-Party Apps to Kobo E-readers
The open-source platform introduces a Rust-based SDK and secure runtime, transforming locked-down e-ink devices into versatile tools.
BandarLabs has released Cobalt, an open-source application platform that allows Kobo e-readers to run third-party applications. The release marks a significant shift for the hardware, moving it beyond a dedicated reading device toward a more flexible e-ink computer.
The Cobalt system consists of a launcher, a signed App Store, and a dedicated runtime designed for security. To protect the device, the runtime isolates each application within its own unprivileged process. Developers can build for the platform using a provided Rust-based SDK. Installation is handled via USB, though once the platform is active, users can manage, update, and remove apps over Wi-Fi. Notably, the installation is non-permanent; a simple reboot of the device returns it to its stock Kobo reader state.
The E-ink Ecosystem
Kobo e-readers typically operate on a locked-down version of Linux utilizing a proprietary user interface known as Nickel. While the enthusiast community has previously used tools like Plato and NickelMenu to extend the devices' capabilities, these modifications often lacked a formal structure. Cobalt builds upon this foundation by integrating directly with NickelMenu to place its entry within the default Kobo menu. As the author of Cobalt noted on Hacker News, "NickelMenu is terrific and Cobalt uses it to show the menu item in the default Kobo menu."
Expanding Hardware Utility
This development transforms the Kobo from a single-purpose e-reader into a versatile e-ink device. By providing a formal SDK and app management system, Cobalt lowers the barrier for power users and developers to create specialized tools—such as terminals, AI chat interfaces, and advanced readers—without the risk of permanently modifying the system firmware. This allows the hardware to serve a wider array of productivity and utility functions while maintaining the battery efficiency of e-ink.
Future Outlook
As an open-source project, the growth of Cobalt will depend on developer adoption of the Rust SDK and the expansion of the signed App Store. While the platform currently enables a wide range of custom tools, the community will be watching to see how many third-party developers migrate their existing e-ink projects to this more structured environment.