Harrison Crettol
Sheet 03 · Jun 2026 · Firebase / AI / Security

The Key
Stays Locked

Vault is a real AI assistant on a public website — and the secret key he runs on never reaches your browser. Ask him how that works. He's right here.

Vault
Online
Hi, I'm Vault 🔒 I look after the secret key this site uses to talk to its AI. Curious how that works? Ask away.

How it works

Your messages never go to Google directly — they go to a small program of mine, which adds the secret key on the server and passes only the answer back. That single hop is the whole trick.

01 / Your browser
This page

Sends your message. No key attached.

02 / My server
/api/chat

Adds the key, calls Gemini, returns only the reply.

🔒 Key stays here

03 / Google
Gemini

Generates the answer and sends it back.

If this page called Gemini directly, the key would be sitting in the source for anyone to copy. It isn't — go look.

Try to break it

Open your browser's developer tools, go to the Network tab, and send Vault a message. You'll see the request to /api/chat — and no API key anywhere in it. That's the whole demo.