India, Sept. 2 -- Ten years ago, the idea of paying a roadside tea seller, an auto-rickshaw driver or a vegetable vendor by scanning a QR code would have seemed extraordinary. Today, it is routine. Few transformations better capture the scale and speed of India's digital revolution than the success of the Unified Payments Interface (UPI).

Introduced in 2016, UPI created an interoperable system allowing different banks and payment applications to operate over common infrastructure. According to the Ministry of Finance, annual UPI transaction volume rose from about 2 crore in FY 2016-17 to more than 24,162 crore in FY 2025-26. At this scale, UPI is no longer simply a convenient way to pay. It is critical economic infrastructure - and infra...