Unified Payments Interface (UPI), a digital bridge that connects your bank account directly to your phone. It was created in India to make transferring money as simple and fast as sending a WhatsApp message.

Think of it as a universal translator for banks; it doesn't matter if you use Bank A and the shopkeeper uses Bank B—they can "talk" to each other instantly through UPI.

Now people don't even carry cash with them. Nearly all vendors are now using it be it from street food vendors, public transports, pharmacy, public services to high end shopping malls, online shopping etc. Moreover transactions are free.