UPI: India built a digital payments miracle. Now comes the bill.

For most Indians, paying by Unified Payments Interface (UPI) has become almost absurdly routine. Scan a QR code, tap a few buttons and the money moves instantly. There is no card machine, no cash, and - most importantly - for the user, no visible fee. India has paved the way for banks and payment companies to charge merchants a fee on UPI transactions, potentially ending a decade-long experiment in free digital payments. The government has yet to decide the rate or exactly where it will apply, but proposals under discussion include a merchant discount rate (MDR) of 0.3-0.5% - a small fee paid by a business to the banks and payment companies that process its UPI payments - on larger transactions at big businesses. The government says consumers and person-to-person UPI payments will remain free. If merchant fees are introduced, they will apply only to some transactions above a set threshold, at a nominal rate, meaning most UPI payments will remain free. The question is whether putting a price on UPI could weaken the network that made it such a success. The stakes are enormous. Launched in 2016, UPI has grown into one of the world's biggest real-time payment networks. According to off