What is UPI?

UPI is India’s Unified Payments Interface. Payers send to a virtual payment address, such as name@bank, and the credit is instant. It is an account-to-account rail on top of the banks that participate. Your product still needs a ledger if you hold balances or sit between two customers.

How does UPI work?

A collect request or a pay request moves through the UPI switch. The payer authenticates. The banks debit and credit immediately. The VPA is an alias, not the ledger wallet. Failures are immediate. There is no ACH-style R01 two days later.

UPI vs holding a wallet

If you only pass through UPI and never owe the customer, you may only need payment records. If you load a wallet from UPI or pay out later, you need a book. The VPA lookup is not that book.

How it works with Blnk

Treat UPI like other instant rails. Credit the wallet from @WorldINR_UPI on a confirmed inbound. Debit the wallet to @PayoutINR_UPI on send. Keep the UPI reference on the transaction.