What Is UPI And How Does This Unique Transaction System Work?

Users across India are experiencing issues with Unified Payments Interface (UPI) transactions, as multiple banking and payment apps, including Google Pay and Paytm, report widespread failures.

According to Downdetector, complaints about service disruptions spiked in the evening, affecting fund transfers, transaction processing, and login access.

NPCI had faced intermittent technical issues owing to which UPI had partial decline. The same has been addressed now and the system has stabilised. Regret the inconvenience.

— NPCI (@NPCI_NPCI) March 26, 2025

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Services Affected

Google Pay: The majority of users (72%) reported problems with payments, while website access and app-related issues accounted for 14% each.

Paytm: Around 86% of complaints were linked to payment failures, followed by login issues (9%) and purchase-related problems (6%).

The outage has caused significant inconvenience to users relying on UPI for seamless digital transactions. Authorities have yet to issue an official statement regarding the root cause of the disruption.

Instant payments refer to financial transactions that are processed and settled within seconds using advanced digital payment systems. These include Real-Time Gross Settlement (RTGS) and Immediate Payment Systems (IPS), which ensure 24/7 real-time fund transfers.

As a fast and secure alternative to traditional banking methods, instant payments enhance user experience and improve the efficiency of digital financial transactions.

What Is Unified Payments Interface (UPI)?

UPI (Unified Payments Interface) is a real-time digital payment system developed by the National Payments Corporation of India (NPCI). It allows seamless money transfers between bank accounts via mobile applications without requiring extensive banking details.

UPI facilitates a range of transactions, including:
✅ Money Transfers – Send and receive funds instantly.
✅ Bill Payments – Pay electricity, water, mobile, and other utility bills.
✅ Online & Offline Purchases – Make payments via QR codes, UPI IDs, or mobile numbers.

By eliminating the need to enter bank details for every transaction, UPI enhances payment convenience using existing systems like Immediate Payment Service (IMPS) and Aadhaar Enabled Payment System (AEPS).

🔗 Related Read: [What is UPI Lite? How Does it Work, and its Benefits]

How Does Unified Payments Interface (UPI) Work?

UPI functions through a simple and efficient framework that ensures seamless digital transactions. Below is a step-by-step breakdown of the process:

Step 1: User Registration

Download a UPI-enabled app like PhonePe, Google Pay, or Paytm.

Link your bank account and create a virtual payment address (VPA) (e.g., user@bankname), which acts as your UPI ID.

Step 2: Initiating a Transaction

Choose a payment method:
🔹 Enter the recipient’s UPI ID (VPA) (e.g., merchant@bankname).
🔹 Scan a QR code at a shop or business.
🔹 Enter a UPI-registered mobile number.

Step 3: Authentication

To authorize the transaction, enter your UPI PIN—a 6-digit secure code set during registration.

This security step ensures that only the account holder can approve payments.

Step 4: Transaction Processing

Once the UPI PIN is entered, the app sends the request to the UPI server.

The server verifies the transaction by communicating with:
🔹 The sender’s bank (issuer bank)
🔹 The recipient’s bank (acquirer bank)

Step 5: Confirmation

After the banks approve the payment, a confirmation message is sent instantly.

Example: “Payment of ₹500 to merchant@bankname successful.”

Step 6: Fund Settlement

While the transaction reflects instantly in the user’s account, the backend settlement between banks is usually completed within a few hours.

This smooth and secure process has contributed to the widespread adoption of UPI payments in India, making it a preferred choice for cashless transactions.

UPI Transaction Flow: How Transactions Are Processed

The UPI transaction flow consists of two types of payment requests:

🔹 Push Transactions (Sender Initiated) – The user sends money to a recipient (e.g., transferring funds to a friend or merchant).

🔹 Pull Transactions (Recipient Initiated) – The recipient requests money from a user (e.g., merchant requests payment after a purchase).

This structured approach ensures secure, real-time transactions, reinforcing UPI’s reliability in India’s digital payments landscape.