Harrison Crettol
Sheet 04 · Jun 2026 · Firebase / Auth / Database

Sign In, Save,
Come Back

Google sign-in on one side, a real cloud database on the other. Rack up a score, save it, then open this page on your phone — the same number is waiting. That's all a login really is.

0
Current score
Welcome!

How it works

This site never sees your password. Google checks it, hands back a signed token with a permanent ID — your uid — and the database only lets that uid touch its own document.

01 / You
One click

Sign in with the Google account you already have.

02 / Google
Their sign-in

Checks the password, returns a signed token with your uid.

🔒 Password stays here

03 / Firestore
users/{uid}

Your score lives in a document filed under your uid.

The uid comes from Google's signed token, not from anything typed into the browser — so the server-side rules can enforce "you may only touch your own document," and editing this page can't get around that.

The actual test

Save a score here, then open this page on your phone and sign in with the same Google account. The number is already there. Nothing was stored on either device.