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2 pieces

How UPI Works

A clear map of what happens behind the scenes when money moves through UPI.

Begin

Pieces in this series

01

How UPI Works

The mechanics of payment instructions, Common Library PIN encryption, two-phase settlement, and interbank clearing

UPI is not a digital wallet and your phone does not move money over the internet. It is a real-time messaging protocol that coordinates authenticated debit and credit instructions across commercial bank ledgers via NPCI's central switch.

02

How UPI Works Without an Internet Connection

Deconstructing USSD cellular signaling, voice telephony IVR, on-device balances, and NFC radio tap-to-pay

Standard UPI requires a live TCP/IP internet connection. When mobile data fails, UPI can operate through alternate physical transport rails: GSM cellular signaling (*99#), voice telephone circuits (UPI 123PAY), on-device bank-bypass ledgers (UPI Lite), and local near-field radio (UPI Lite X).

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