Rice Basket Queen is the name of a stall run by Ms Ruri Ruhyaty in a bustling suburb of Jakarta. A year ago, it was typical of thousands of others. Ms Ruri would place her fish and vegetable dishes on banana leaves on the front counter and wait for customers to walk by.

Then she signed up with Grab, a food delivery and digital payment start-up that is one of the leaders of South-east Asia's fintech revolution. Now her food is delivered to diners on the back of motorbikes through miles of traffic-snarled streets in the Indonesian capital. Her accounting system has evolved from a pen and scraps of paper to an automatically updated digital log. Clients who used to hand over cash now pay with a smartphone app.