NFC Cadeau Tag
handmade, more or less
Give it with a small present. The birthday person holds their phone to it and sees who gave what, what it's for, and the message you wrote with it.
Scan the QR code that came with the card.
That link is yours. Keep it safe, because it's also how you'll read the bank account number later.
This is an experiment, not a shop. No money goes through this system. You transfer it yourself, from your own bank.