Domestic
PAYMENTS SIGNAL · REFERENCE CARDIndia UPI — Unified Payments Interface
Riya pays Arjun INR 250 in seconds by entering his UPI ID, never sharing an account number; the money reaches Arjun instantly while the banks settle net later at the RBI.
Actors
- Riya (payer)customer
- Bank Alfa (Riya's bank / PSP app)bank
- UPI / NPCI (the switch)infrastructure
- Nordbank (Arjun's bank)bank
- Arjun (payee)customer
- Reserve Bank of India (settlement)infrastructure
Messages
- UPI collect / pay request
- UPI pay request
The sequence
| # | Step | Route | Kind |
|---|---|---|---|
| 1 | Enter UPI ID — Riya enters Arjun's UPI ID — no account number shared | Riya → Bank Alfa | message |
| 2 | Resolve VPA — UPI / NPCI resolves the UPI ID to Arjun's account | Bank Alfa → UPI / NPCI | message |
| 3 | PIN & debit — Riya authenticates with her UPI PIN and Bank Alfa debits her | Bank Alfa | posting |
| 4 | Credit Arjun — Nordbank credits Arjun within seconds | Nordbank | posting |
| 5 | Funds usable — Arjun can spend the money immediately | Arjun | internal |
| 6 | Deferred-net settlement — Later, NPCI settles the net positions at the RBI | UPI / NPCI → RBI | settlement |
Exception rails
| Rail | Trigger | Where the money ends up | Next action |
|---|---|---|---|
| UPI ID does not resolve | The VPA cannot be matched to a valid account — a typo like arjunn@bankalfa, or a handle that was deregistered — so NPCI has nowhere to send the money. | Never left Riya's account — no debit was ever attempted. · Nothing to settle; the payment failed before any posting or settlement. | Riya — Riya re-checks the UPI ID (or asks Arjun to reshare his QR) and tries again once a valid handle is entered. |