3wsafebox is a file sharing service owned and used by the widely popular freistellen.de that allows users to upload up to 2GB of files through a single shareable download link that can be sent automatically via email. Each upload made using 3wsafebox can be encrypted and protected with a password.

The challenge was to provide a WeTransfer like experience with resume, pause and a huge amount of uploads simultaneously.

The hardest thing though was to debug the process of uploading and receiving files on the frontend side. Every browser/hardware/internet channel stack is different and sometimes debugging was tricky.