Decimen Optical Transfer is a web-based file transfer tool that uses fountain-coded QR codes displayed on a screen and captured by a camera to move files between devices without any network connection.
The tool solves the problem of transferring files between nearby devices when no network path exists between them. One device displays a file as an endless stream of animated QR codes while another device's camera reads the codes and reconstructs the original file. The approach uses fountain coding, which means the sender can generate QR codes indefinitely until the receiver has enough data to reconstruct the file, making the transfer resilient to partial captures or poor camera angles. Files up to 64 MB are supported, with filename and media type preserved, and transfers are verified with SHA-256 checksums before delivery.
The tool requires no installation, no app pairing, and no special permissions beyond camera access. It works offline after an initial visit and can be installed as a home screen app on iOS and Android. The interface supports twelve languages with localized layouts. Anyone considering adoption should know that the transfer is not encrypted—whatever appears on the sending screen is readable by any camera pointed at it. The design prioritizes network independence rather than confidentiality. The tool suits scenarios where two devices are physically near each other but lack a shared network, such as transferring files in offline environments, across air-gapped systems, or during presentations where a camera can capture content from a screen.
Development activity shows consistent measurement and documentation of performance characteristics, with sustained transfer speeds recorded across different device pairs and linked to full diagnostic reports. The project maintains a multilingual interface with explicit tracking of translation review status by native speakers. The codebase is written in TypeScript and deployed as a progressive web application accessible through a live homepage.
