Privacy

Last updated 7 August 2026.

This website

This site collects nothing about you.

There are no analytics, no tracking pixels, no advertising, and no cookies. No scripts from other companies run on these pages, and there are no forms to submit anything to. Nothing you do here is recorded by us, because there is nothing here to do the recording.

The site is a set of static files hosted by GitHub Pages. GitHub serves them and, like any web server, sees the requests that reach it — your IP address, the page you asked for, and your browser’s user agent. That is between you and GitHub, and it is covered by GitHub’s privacy statement. We do not have access to those logs and do not receive any report derived from them.

Pages that link outward — to Seeed Studio, to Heltec, to GitHub Sponsors — take you to sites with their own practices, which are their own business and not covered here.

The firmware flasher

The flasher, once it exists, will run entirely inside your browser. It will download firmware images from this site and from the project’s GitHub releases, and it will talk to the radio you plug in through your browser’s serial interface. Your browser will ask your permission before it can see any device at all, and that permission covers only the one device you pick.

Nothing about your device is uploaded anywhere. There is no server side to this — the page has nowhere to send anything even if it wanted to.

The iPhone app

The app collects no analytics and contains no third-party software development kits. It has no account system, so there is nothing to sign up for and nothing to sign in to.

Your identity is an encryption key generated on your phone. It is stored in the iOS keychain, marked as belonging to that device alone, which means it is excluded from backups and never syncs to iCloud or to another device. Nobody else — including us — ever holds a copy. If you lose the phone, that identity is gone, and a new one takes its place.

Messages travel over radio, directly between devices, encrypted to the recipient’s key. They do not pass through any server we operate, because there is no server we operate.

Location sharing is off until you switch it on. When you do turn it on, your position goes out over the radio to the channel or contact you chose, exactly like any other message.

The protocol itself

Radio is a shared medium, and anyone nearby with a receiver can hear that something was transmitted. UMSH is designed to give away as little as possible beyond that: addresses travel as short hints rather than as identities, encrypted multicast conceals who sent a packet, and blind unicast can make a private message look like ordinary channel traffic.

None of this hides the fact that a radio transmitted, and none of it defeats someone with direction-finding equipment. If that is part of your threat model, read the security chapter and the limitations chapter before relying on anything here.

Changes

If this page changes in a way that matters, the date at the top changes with it. The full history of this page is public in the project’s git repository.

Contact

Questions about any of this belong in an issue on GitHub.