Engineers who have worked on UPI: why do failed transactions take days to reverse when the rule says T+1?

Arre, finally a journalist asking before writing 😄 I work at a UPI startup, so this is how I understand it from the inside, not an official word. The flow: your app sends the request to NPCI. NPCI asks your bank (the remitter) to debit you. Debit succeeds. NPCI then asks the payee's bank (the beneficiary) to credit them. Most failures happen at this step: the beneficiary bank's system times out or answers late. Now the problem. Your bank has debited you, and NPCI never got a clean yes or no from the other bank. If they reverse you immediately and the credit actually went through, money is created out of thin air. So the transaction is marked "deemed approved": treated as credited until someone proves otherwise. Then reconciliation. Banks get settlement files from NPCI several times a day. The beneficiary bank has to confirm whether it credited or not, and return the money if it did not. Only after that can your bank reverse you cleanly. Why it is slower than T+1: the slow party is the beneficiary bank, which is not even your bank. Your bank's customer care honestly cannot see what the other bank did. And many banks only start chasing once a complaint is filed. Compensation: in practice most banks pay it only when you ask, and most customers do not know it exists. That part is your story, honestly.