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Saurabh Kumar Rai
Saurabh Kumar Rai

Posted on • Originally published at codeopstrek.com

How UPI Actually Works: Your Money Never Really Moves

You tap "Pay" on PhonePe. ₹500 leaves your account.
Your sabziwala's phone beeps. Done. Under two seconds.

But here's what nobody tells you: your bank never actually sent that money.

Not in that moment. Not even close.

Meet the Players

Role Who
Payer You. Sending money.
Payee The merchant receiving it.
Issuer Bank Your bank (HDFC, SBI etc.)
Acquirer Bank Merchant's bank (Axis, Kotak etc.)
NPCI Traffic controller of every UPI transaction.
RBI India's central bank. Every bank holds reserves here.
RTGS RBI's engine that actually moves real money between banks.

What Happens in Those 1.5 Seconds

Step 1: Your UPI app sends a request to NPCI —
"User X wants to send ₹50 to Merchant Y."

Step 2: NPCI contacts your bank — "Debit ₹50 now."
Your bank debits you. But it does NOT wire money to the merchant's bank.
It just records: "We owe ₹50 to the system."

Step 3: NPCI simultaneously tells merchant's bank — "Credit ₹50 now."
Merchant gets the money. His bank records: "NPCI owes us ₹50."

Step 4: Green tick. Done. Under 2 seconds.

💡 The money moved? No.
The ledgers updated? Yes.
Transaction complete? Absolutely.


🔎 But wait — banks can't keep IOUs forever.
Who actually settles the real money?
And how does UPI work on a ₹700 keypad phone with zero internet?

Full breakdown with flow diagram →
codeopstrek.com/how-upi-actually-works-banks-dont-transfer-money

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