InterviewSam
Log inStart free
Interview questions
API designHardSDE-3

A client calls POST /transfers to send money via UPI. Your server calls the bank, and the bank times out. What do you return to the client, and how does the API stay correct?

Asked at
CREDGrowwPaytmPhonePeRazorpay

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: Distributed transactions: 2PC and sagas

Saved on this device. Create a free account to keep it on every device.

Practise this with Sam

A real mock interview, out loud, with an honest scorecard. Free to start.

Start free