Building a genuinely private location app

Welcome to the Fenzly developer journal.

Most location-sharing apps run on a simple trade: you hand over your position all the time, they give you a service back. The catch is that your position ends up in a database they can read, analyse, and sometimes sell.

We wanted to flip the problem around: what if the server simply couldn’t see where you are?

That’s the blind server idea. Your coordinates are end-to-end encrypted with the Signal protocol, your places and circles never leave your phone in the clear, and the “I’ve arrived home” detection happens entirely on your device.

In upcoming posts we’ll walk through the concrete engineering choices — per-member encryption, split-key backups, sovereign hosting in Switzerland. Not marketing: the real decisions, with their trade-offs.