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Payments & fintechHardSDE-3

On Diwali sale night your UPI payment volume is 10x normal, and one large bank's servers start timing out, dragging down your overall success rate and filling your thread pools. How should the system be designed to cope?

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FlipkartPaytmPhonePe

Think first

Answer out loud as you would in the room — clarify, give numbers, name the trade-off — then compare with the model answer.

Go deeper

Design UPI payments (PhonePe / Google Pay) Lesson: Concurrency, backpressure and load shedding

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