By – Dr. Kammula Sunil Kumar
Assistant Professor, CSE Department, SRM University -AP ( Amaravati)
UPI payment is usually pictured the same way: a smartphone, a QR code, an internet connection, and a tap. That picture leaves out a large part of the country. India still has an estimated 400 million feature phone users, people who either cannot afford a smartphone or live in areas where data coverage is patchy at best. For years, this group sat outside India’s digital payments boom, watching a revolution they could not fully join. UPI 123PAY was built specifically to close that gap, and its underlying idea is worth pausing on: a UPI payment that needs neither a smartphone nor an internet connection to complete.
Launched by the National Payments Corporation of India (NPCI) in March 2022, in coordination with the Reserve Bank of India (RBI), UPI 123PAY works through four alternative methods rather than the usual scan-and-pay app. The first is an interactive voice response call, where a user dials a designated number, follows spoken prompts in a language of their choice, selects an option such as paying a merchant, and confirms with a UPI PIN. The second is a missed-call method, where dialing a number linked to a specific biller or merchant triggers a callback and guided payment. The third allows selected phones to run a simplified, pre-loaded UPI app that mimics smartphone functionality within a lighter interface. The fourth, and the most technically distinctive, is sound-based proximity payment, where a phone communicates with a merchant’s device using audible sound waves rather than the internet, allowing a payment to be completed even where no data signal exists at all.
Setting this up follows a process familiar to any UPI user, adapted for a phone without a touchscreen or apps: a bank account is linked to the phone number, a UPI PIN is created, and from that point on, the same two-factor authentication that protects a smartphone transaction protects a feature-phone one. The service does carry some deliberate limits: a maximum of ten thousand rupees per transaction and one lakh rupees a day, one linked bank account at a time, and no scan-and-pay option, since there is no camera or app screen to read a QR code. These are not oversights so much as a recognition that this channel is meant for routine, small-value transactions, recharges, bill payments, small merchant purchases, rather than as a full replacement for smartphone-based UPI. The fintech engineering behind this is worth unpacking, because UPI 123PAY did not invent offline UPI access from scratch; it replaced a channel that already existed but had quietly failed. Since 2012, feature phone users could technically reach UPI through the National Unified USSD Platform, dialing the short code star-99-hash, a service built on USSD, a text-based signalling protocol that piggybacks on the same GSM control channel mobile towers use to manage calls, rather than on mobile data. It worked, but it never caught on: USSD sessions are slow, menu-driven, prone to timing out mid-transaction, and telecom operators charged a small per-session fee for every attempt, friction that discouraged repeat use. UPI 123PAY was designed as NUUP’s more usable successor. Its IVR and missed-call methods run over the ordinary voice call network instead of a data session, using Dual Tone Multi-Frequency signaling, the same tones a phone generates when a keypad button is pressed, to transmit menu choices and PIN entries during the call. Because a voice call, rather than a USSD or data session, carries the interaction, the experience is closer to talking to an automated bank helpline than navigating a text menu.
Underneath these feature-phone-specific front ends, though, the transaction still travels through the same backend architecture as any smartphone UPI payment. NPCI operates the central UPI switch, the hub that authenticates the request, checks it against the two-factor UPI PIN and registered device or number, and routes it in real time between the payer’s bank and the payee’s bank, both of which participate as Payment Service Provider banks within the network. In other words, 123PAY changes how a customer’s phone talks to the system; it does not change how the system itself moves and settles money. The sound-based proximity method is the one genuine exception at the transmission layer: it encodes payment data as an audible frequency pattern exchanged directly between the customer’s and merchant’s devices over the air, a technique borrowed from proximity-payment research elsewhere, meaning the local handshake between two phones needs no network at all, even though the underlying settlement between banks still ultimately requires connectivity for one side of the transaction, typically the merchant’s device.
What makes this significant is less the technology itself than what it quietly assumes about who deserves access to digital payments. Much of the conversation around India’s UPI success, now the world’s largest system by transaction volume, tends to centre on smartphone adoption, app design, and merchant QR codes in cities. UPI 123PAY represents a different, less visible frontier: rural India, elderly users unfamiliar with apps, low-income households where a basic phone is a rational economic choice, and regions where network towers still do not support reliable 4G. For a shopkeeper in a small town, or a daily-wage worker managing money on a keypad phone, this service offers something a QR-based app never could, digital payment without the prerequisite of owning a smartphone or paying for data. There is also a quieter economic argument sitting alongside the social one. Cash carries real, if often uncounted, costs, the risk of theft, the physical burden of storage and transport, the friction of making exact change, and the parallel economy it enables. Extending UPI’s reach to feature phones is, in effect, an attempt to fold a very large population directly into a formal, traceable, and secure payment system without asking them to first buy a different phone. Whether that ambition fully succeeds depends on adoption, and adoption data on 123PAY specifically remains far behind smartphone UPI, a signal that awareness and habit-building among this user base still lag the technology’s availability.
That gap between capability and uptake deserves honest acknowledgement rather than a triumphant close. Building a payment rail that works without a smartphone, or internet connection is a genuine technical and policy achievement, but a feature phone user typically has fewer number of touchpoints nudging them toward digital payments than a smartphone user does, no colorful app icon, no push notification, no cashback banner. Bank correspondents, local self-help groups, and merchant associations are likely to matter more here than advertising, since trust in a new payment method, especially for users less familiar with digital finance, tends to travel through people rather than platforms. UPI 123PAY has solved the harder problem, making the payment technically possible without a smartphone; whether it becomes a habit for the population it was built for is still an open, largely unfinished chapter of India’s digital payments story.
