How QR codes revolutionised Indian commerce

The little QR code is ubiquitous across India’s vastness.

You find it pasted on a tree next to a roadside barber, propped on the pile of embroidery sold by women weavers, sticking out of a mound of freshly roasted peanuts on a snack cart. A beachside performer in Mumbai places it on his donations can before beginning his robot act; a Delhi beggar flashes it through your car’s window when you plead that you have no cash.

The codes connect hundreds of millions of people in an instant payment system that has revolutionised Indian commerce. Billions of mobile app transactions — a volume dwarfing anything in the West —