In Bali the deposit on a rented scooter is often your passport. At return the shop points at a dent, you say it was already there, and whoever is holding the document wins the argument.

I built Jaminan for the PayPal AI Hackathon to replace the passport with something both sides can check: a PayPal authorization that can only pay for lines the renter accepted. The part worth writing about is not the AI. It is how little code it takes to make PayPal itself refuse the wrong settlement, and the places the sandbox disagreed with my first design.

Everything below ran on the PayPal sandbox . Code: https://github.com/edycutjong/jaminan . Live: https://jaminan.edycu.dev/app/judge (one tap, fresh sandbox rental). Demo video (2:56): https://youtu.be/E8r-QMLocQo .…