Paytm made Vijay Shekhar Sharma the face of Indian fintech. Smartphones were spreading, and then in November 2016 demonetisation emptied the country's wallets overnight and pushed millions of people onto digital payments in a matter of weeks. Few founders have ever caught a wave that size.

The company became a full financial-services platform — payments, commerce, lending — backed by marquee global investors, with a brand so ubiquitous that 'Paytm karo' entered the language. Its listing was among the largest India had seen.

He wanted payments to be as ordinary as breathing. For a while, an entire country moved to his rhythm.

What followed was harder. The share price fell steeply after listing, regulators tightened around parts of the business, and both the company and its founder had to prove they could operate under scrutiny. Profitability and compliance replaced growth as the things that mattered.

His arc is Indian fintech's arc in miniature. A founder from a small town helps normalise digital money for a billion people, then has to demonstrate the business still works once the era of growth at any cost ends.