UPI: Anatomy of a Transaction
‹ All reads scan<br>name & amount<br>PIN<br>the part you never see<br>payment sent<br>received
The five moments of a UPI payment as you experience them. Everything between your PIN and the result happens out of sight. Several times a day, most of us pay the same way. You hold your phone up to a printed<br>code, check the name that appears, enter the amount, key in a PIN, and a green tick says it<br>is done. On<br>the other side, someone’s phone buzzes to say the money has arrived. Start to finish,<br>two or three seconds.<br>Those five moments, the scan, the name and amount, the PIN, the tick, and the buzz on the<br>other side, are the whole payment as you ever see it. Everything else is hidden. Between the<br>scan and the tick your instruction runs through a short chain of separate organisations, each<br>checking one thing and handing the result to the next, all of it finishing before you have<br>looked up from the screen. The app on your phone is only the first link, and it never touches<br>your money.<br>It is worth knowing how much rides on this quiet handover. In<br>June 2026 alone UPI carried more than<br>2,272 crore payments, more than any other real-time payment system<br>in the world.5<br>This piece fills in the gap between the scan and the green tick. We follow a single payment<br>down the chain, one party at a time: who hands it to whom, what each one checks, and where<br>it can fail. At every stop we also look at how that part has changed. The diagram below is<br>the whole cast, and we begin at the top, with the part you are holding.<br>Your appPhonePe, GPay<br>Your PSPissues your @handle<br>Your bankmoney out ⊖<br>NPCIthe switch<br>Payee bankmoney in ⊕<br>Payee PSPowns payee @handle<br>Payee appshows received
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Every actor in one payment. NPCI sits in the middle and trades request-and-reply<br>messages with all four legs. The receiver’s side mirrors yours. The app<br>The first part is the one you already know: the app. PhonePe,<br>Google Pay, Paytm, or one of a dozen others. It is easy to take the app for the payment<br>system itself, but its actual job is narrow. In the system’s own language it is a<br>Third-Party Application Provider: it gathers your intent — pay this person, this amount<br>— shows you who you are about to pay, and collects your PIN through a secure pad it<br>cannot read into.<br>Then it hands the instruction on. It never sees your PIN, holds none of your money, and carries<br>no banking licence.1<br>This thin layer is where almost all of UPI’s competition is fought, and the contest is<br>lopsided. Two apps, PhonePe and Google Pay,<br>between them carry about four-fifths of every UPI payment; everyone else divides the<br>rest.10 That duopoly has held for years. What moves is<br>the order beneath it.<br>Watch the ranking over the years. A newcomer, super.money,<br>launched by Flipkart in 2024, climbs from outside the top fifty into the top five in about a<br>year, pulling users in with guaranteed cashback.810<br>The two apps at the top barely shift; the floor below them never stops rearranging.
Rank of the leading UPI apps by yearly transaction volume. Source: NPCI app<br>statistics.10 For all that competition, there is one thing none of these apps can do on their own: reach<br>the payment network. For that, each of them has to stand behind a bank.<br>The sponsor<br>Because the app holds no licence<br>and no direct line to the payment network, it has to borrow both from a partner bank called a<br>Payment Service Provider, or PSP, its sponsor. The sponsor does the<br>things the app cannot: it connects to the central system, it issues the UPI address that stands<br>for you, and it is the party that first tied your phone to your bank account when you set<br>UPI up.1<br>That address is more revealing than it looks. The suffix on a UPI ID, the part after the<br>@, names the sponsor bank, not the app you are using. An address<br>ending in @ybl sits on Yes Bank; one ending in<br>@okaxis sits on Axis. PhonePe’s handles run on Yes Bank,<br>Axis and ICICI; Google Pay’s on Axis, HDFC, ICICI and State<br>Bank.7<br>Most of the big apps now sit on several sponsor banks at once rather than one, mainly for<br>resilience: spread across banks, a single bank’s outage cannot take the whole app<br>offline, and no one sponsor has to carry all of the app’s volume.7<br>The sponsor banks get a quieter benefit of their own. When a payer and a payee happen to sit on<br>the same sponsor, that bank resolves both addresses in its own books and skips the<br>network’s central directory — faster, and it saves the resolution fee of about a<br>paisa.7<br>So what actually leaves your phone is not money. It is a request assembled by the app and<br>signed by your sponsor bank. Three of the five moments you see live here: the scan, the name<br>and amount, and your PIN. The name is the network confirming who holds the address you scanned, your one<br>chance to catch a wrong payee before any money moves. The PIN is captured and encrypted by a<br>certified component on your phone; the app passing it along never...