A museum specimen label: the age engraved on a brass accession plate, the code as the plate, and the record resting on the foot.
Half an A4 sheet. Two per page if your printer can do it. This is the ink-saving version: white paper, the party's accent kept and nudged until it stays legible on it. Switch back to Full colour for the version that looks like the party.
The code goes to the invitation site itself, so a guest who scans it lands on the countdown, the address and the RSVP — not on an app store.
Mateo is invented and so is his party — the QR on this sheet opens the matching sample invitation. Yours carries your child’s name and links to your own invite.