How Does a QR Code Work? The Science Behind Every UPI Payment

There was a time when paying for a Rs 20 ice cream meant checking your wallet for change. A Rs 35 packet of vegetables could leave you counting coins in your palm. And if the exact amount wasn’t there, someone had to make a quick trip to a nearby shop for change. Today, the same ice cream vendor may simply point to a small black-and-white square stuck beside the cart. So does the neighbourhood vegetable seller So does the chai stall, the local kirana shop and the roadside momo vendor. From roadside ice cream carts to neighbourhood kirana shops, QR codes have made digital payments possible w...