What the relay cannot see

pairfob.com is this project's official relay. It does not run Herdr. Provided the devices and client code have not been tampered with, the session is end-to-end encrypted after pairing, and keys live only on your device and on the computer.

The relay forwards ciphertext and cannot see the session, what you type, or the agent conversation. It can see the identifiers needed to reach the right computer and the connection source used to rate-limit abuse.

On a P2P path, session bytes do not go through pairfob.com; the relay still only sees the ciphertext used to set up that path. To find a direct path, the browser asks Cloudflare’s public-address lookup, which sees this device’s public address. Pairfob does not run a bypass for firewalls; if a direct path cannot be found, the session stays on the relay.

Trust in the website's code

The browser's encryption and decryption code comes from pairfob.com, so you still need to trust the official site and its code publishing channel. If the site operator or someone who controls that channel serves malicious code, it could read and send out keys or plaintext. End-to-end encryption cannot protect a client that has been tampered with.

Adding the PWA to your Home Screen still allows updates from the site; it does not pin a trusted version. The guarantees about the relay's access to session contents depend on trusted devices and client code.

The computer only dials out

You do not open ports at home and you do not bind Tailscale. The computer connects out to pairfob.com.

Enter on the computer is what actually admits a device. Someone who only photographed the QR cannot pair.

Where credentials live

Place	What
Pairfob’s config directory on the computer	This computer’s identity and paired devices. Treat it as a password; do not paste it into chat
This device’s browser	This device’s credential. Clearing site data means pairing again
pairfob.com	Ids needed to route. No session contents

Out of scope

• Malicious control of the official website's code or publishing channel
• A fake Pairfob page — use https://pairfob.com
• A stolen phone that is still paired
• Someone who already has the unlocked computer

If something is wrong

1. pairfob list on the computer and forget anything that should not be there
2. If the computer itself is unclean: stop the service, clean the machine, reinstall

Do not paste pairing codes into someone else’s page.