218 million a year, and orders aren't the hard part

transcript

218 million transactions in a year. That's only 7 a second. So why is this network hard to scale?

ONDC, financial year 2025 to 26. About 7 a second, on average. Assume a festival evening at ten times that. About 70. Design for three times the peak. 200 a second. Tiny.

But here's the catch. Search isn't an order. On an open network, every search is a broadcast.

A buyer types brass thali. Her app asks the gateway. The gateway multicasts it to every seller app in that city. Assume 150 of them. And the search waits for the slowest.

Orders at the design target: 200 a second. Every signed call inside those orders: about 5,000. Assume 1,000 searches a second, broadcast live. 150,000 calls.

So don't broadcast every search. Pull each city's whole catalogue, once. Take updates every 1 to 30 minutes. Then search your own index. In milliseconds.

The cached stock is just a hint. The seller app checks it at select. Broadcasts don't scale per query. So pay once.

Full breakdown in the lecture.