Your order went out. Then the line dropped.

transcript

9:15. Your buy order leaves for the exchange. Then the line drops. No answer. Is your order at the exchange? Nobody knows.

Resend it? It may already be resting at the exchange. Then you've got two orders. Double the shares. Tell you it failed? You'll just place it again yourself. Same duplicate. Different finger.

This really happened. February 2019, at the open. Several lakh orders sat in validation pending. So customers placed more orders, to make up for the hanging ones. Zerodha's own words: the pile-up grew exponentially.

So mark it sent before the bytes leave. Then a crash can't forget it. No answer in 2 seconds? It becomes its own state. Unknown. Ask the exchange, by broker reference, through the other data centre. Found? It's open. Not found, even after a full resync? Not placed. Margin released.

Meanwhile, the screen tells the truth. Sent to the exchange, confirming. Don't place it again. That one line stops the second tap. Then it flips. Open at the exchange.

Two seconds of silence, and it's unknown. The target: 99 point 9 percent resolved within 30 seconds. Every last one within 5 minutes.

A timeout doesn't mean failed. It means I don't know. And from I don't know, you ask. You never act again.

Full breakdown in the lecture.