What Is UPI? How the Unified Payments Interface Works

Search Fintrev

Search our guides, reviews and glossary.

The Unified Payments Interface (UPI) is India’s real-time payment system for moving money directly between bank accounts through a smartphone app. The National Payments Corporation of India (NPCI) developed and operates it, and the Reserve Bank of India (RBI), the country’s central bank, regulates it. A sender pays to a simple identifier, such as a virtual ID, instead of typing in the recipient’s full bank details, and authorizes each payment with a personal UPI PIN.

UPI is a shared interface, not a single app. Banks and payment apps connect to it, which is why the same UPI ID can receive money from customers of many different banks.

How UPI works

A UPI payment links three things: a bank account, a mobile phone, and an identifier. When a user sets up a UPI-enabled app, they connect one or more bank accounts and create a virtual payment address (often called a UPI ID). They also set a UPI PIN, which works as the authorization step for outgoing money.

Once that identifier exists, the user can pay someone without a debit card, a credit card, net banking credentials, or the recipient’s account number. The app sends the payment instruction through the UPI network, and the transfer settles between the two banks over the underlying rails such as IMPS. Because the system runs in real time, the transfer is designed to complete within moments, and both parties receive a confirmation.

Depending on the app and the transaction, other identifiers can also route a payment: the recipient’s account number plus the Indian Financial System Code (IFSC, an alphanumeric code that identifies a bank branch for electronic transfers), a registered mobile number, or an Aadhaar number (India’s national identity number).

Besides sending and receiving, UPI apps let users check account balances and view transaction history for linked accounts.

Sending vs. receiving: push and pull

Push (sending). The payer opens the app, chooses the send or pay option, enters the recipient’s virtual ID and the amount, selects which linked bank account to debit, and enters the UPI PIN. The money is sent and a confirmation follows.

Pull (collecting). The person who wants to be paid chooses the collect option, enters the payer’s virtual ID, the amount, and the account that should receive the funds. The payer then gets a payment request. Nothing moves until the payer approves it by entering their own UPI PIN. After the transfer, both sides get a confirmation message.

In both cases the PIN is entered by the person whose money is leaving. Entering a PIN always means paying, never receiving.

Example of a UPI payment

Hypothetical example for illustration only. Priya owes her friend Arjun ₹1,500 for concert tickets. Arjun’s UPI ID is linked to his savings account at one bank; Priya banks somewhere else.

1. Priya opens her UPI app and selects Send Money.
2. She enters Arjun’s UPI ID and ₹1,500.
3. She chooses her linked savings account as the source.
4. She enters her UPI PIN.
5. Her bank debits ₹1,500, the payment settles to Arjun’s bank, and both receive a confirmation.

Neither of them shared an account number or IFSC. If Arjun had instead sent Priya a collect request for ₹1,500, the result would be the same, but only after Priya approved the request with her PIN.

What UPI is used for

UPI started with peer-to-peer and interbank transfers, and its scope widened to cover:

• Person-to-person transfers, such as splitting bills or sending money to family.
• Merchant payments, including over-the-counter purchases and scanning a barcode or QR code at a shop.
• Recurring payments, such as utility bills, school fees and subscriptions.
• Inbound remittances, where international transfer services such as Wise, WorldRemit and Remitly let senders abroad, including in the U.S., pay a recipient in India using the recipient’s UPI ID. The recipient receives the funds into the bank account linked to that ID.

Its scale grew quickly. About $940 billion moved over UPI in 2021, and by 2022 the system averaged more than six billion transactions a month, making UPI a central part of India’s digital payments growth.

UPI vs. similar payment tools

UPI vs. a digital wallet. A digital wallet often holds a stored balance or tokenized cards inside the app. UPI moves money directly between bank accounts. Many Indian apps offer both a wallet and UPI, so the funding source is worth checking before you pay.

UPI vs. IMPS. IMPS is an older real-time interbank transfer service. UPI sits on top of it as an interface layer, adding virtual IDs, PIN authorization, collect requests and app access.

UPI vs. a UPI app. BHIM, Google Pay, PhonePe and Axis Pay are apps that connect to UPI. The network is the same; the app is the front end. A UPI ID created in one app still sends to and receives from users of other UPI apps.

UPI vs. U.S. peer-to-peer apps. Services like Venmo and PayPal are individual companies’ networks that users join. UPI is national infrastructure that many banks and apps plug into, which makes it closer to a public payment rail than a single product.

Limitations and risks

Built for India. UPI is tied to Indian bank accounts and identifiers. People outside India generally reach it only indirectly, for example through a remittance service that delivers funds to a recipient’s UPI ID, rather than by holding a UPI account themselves.

Speed cuts both ways. Real-time settlement means a payment sent to the wrong UPI ID, or approved by mistake, leaves the account immediately. There is no clearing delay in which to stop it.

Collect requests can be misused. Because a pull request asks the payer to enter a PIN, a fraudster can send a request labeled as a refund or prize. Approving it sends money out. Regulation by the RBI governs the system, but it does not stop a user from authorizing a payment they did not intend.

Requires a smartphone and bank account. UPI widens access for banked smartphone users. People without either still need other payment methods.

The Bottom Line

UPI matters to anyone in India who pays friends, shops or bills from a bank account, and to senders abroad who use remittance services to reach a recipient's UPI ID. Payments settle in moments without sharing account numbers, but that speed means mistakes and approved scam requests leave the account immediately. Check the UPI ID before paying, and remember that entering a PIN always sends money out.