If you have sent money using a UPI app, pulled out a document from DigiLocker, or applied for a loan that was approved in minutes, you have already touched India's digital public infrastructure — probably without thinking twice about it. These systems have become invisible in the best possible way: they just work.
But understanding what they are, why they were built the way they were, and how they connect to each other is genuinely useful — especially if you run a small business, or if you are curious about why India's digital services feel different from what exists in most other countries.
This article walks through the main building blocks, layer by layer.
What Is Digital Public Infrastructure?
Digital public infrastructure (DPI) refers to foundational technology systems built to serve the entire population, not a single company's users. Think of it the way you think of roads or electricity grids — shared infrastructure that any business or individual can use, rather than a proprietary service locked to one provider.
India has assembled one of the most complete DPI stacks in the world over roughly fifteen years. The layers are sometimes called "India Stack," and they span identity, payments, documents, financial data sharing, and now commerce.
Layer 1: Aadhaar — A Shared Identity Rail
Aadhaar is a 12-digit biometric identity number issued by the Unique Identification Authority of India (UIDAI). As of 2024, over 1.3 billion enrollments have been issued, making it one of the largest identity systems ever built.
What makes Aadhaar infrastructure (rather than just a card) is the Authentication API. Any authorised service can ask: "Is the person presenting this Aadhaar number really who they say they are?" The answer comes back as a yes/no — with the actual biometric data staying at UIDAI. This matters because it means a bank branch, a telecom operator, or a government office can verify identity digitally without copying and storing all your personal documents.
For ordinary people, this translated into faster and cheaper bank account openings (the Jan Dhan accounts), mobile SIM verification, and paperless government benefit delivery.
For small businesses, it lowered the cost of KYC — the regulatory requirement to "know your customer." A paperless KYC that previously cost a lender hundreds of rupees can now cost a few rupees via the Aadhaar e-KYC API.
Layer 2: UPI — Instant, Interoperable Payments
The Unified Payments Interface, launched by the National Payments Corporation of India (NPCI) in 2016, is the payment rail that most Indians now use daily. In June 2024 alone, over 13 billion UPI transactions were processed.
The key design choice was interoperability. A person using PhonePe can pay someone using Google Pay or Paytm or any bank app, and the money moves in real time, 24/7, including weekends and public holidays. No single company owns the rail — NPCI operates the switch and any bank or payment app can plug in.
This is fundamentally different from how payment systems had worked before, where each wallet or card network was a walled garden. UPI made it so that the "network" is not controlled by a company but is shared infrastructure.
For small businesses, it removed the need for expensive point-of-sale machines. A printed QR code is enough. A street-food vendor, a small shop, or a domestic worker can now receive digital payments with essentially zero infrastructure cost.
Layer 3: DigiLocker — Documents That Follow You
DigiLocker is a cloud-based document wallet operated by the Ministry of Electronics and Information Technology. Over 250 million users have accounts, and the platform holds more than 6 billion documents.
The idea is straightforward: instead of carrying physical copies of your driving licence, vehicle registration, class 10 marksheet, or income tax returns, these documents live in DigiLocker. When a government office, bank, or other authorised entity needs to verify one, they can pull the official, digitally signed version directly from the issuing authority — not a scanned copy you submitted.
This has practical consequences. Universities can verify degrees. Banks can verify income documents. Traffic police can accept a DigiLocker-linked driving licence shown on a phone. The documents are legally equivalent to originals under the IT Act.
Layer 4: Account Aggregator — Your Financial Data, Portable and Consented
The Account Aggregator (AA) framework, launched in 2021, is less well-known but perhaps the most consequential for financial inclusion.
Before AA, if you applied for a loan at Bank B but your salary account was at Bank A, you had to print statements, get them stamped, and submit physical copies. The process was slow, error-prone, and often required branch visits.
Account Aggregator creates a consent-based data-sharing layer. You can authorise Bank A to share your statements electronically — in a structured, machine-readable format — with Bank B, or with a lending app, or with an insurance company. The data flows only with your explicit, time-limited consent. The aggregator itself cannot read or store the data it is passing.
For small businesses and self-employed workers who lack formal payslips, this opens credit access that was previously very difficult to obtain. A lender can see actual GST returns, bank cash flows, and tax data — with your permission — rather than relying only on payslips and employer letters.
Layer 5: ONDC — Open Rails for Commerce
The Open Network for Digital Commerce (ONDC) extends the DPI philosophy to buying and selling goods and services. Where UPI made payments interoperable, ONDC aims to make commerce interoperable.
Before ONDC, if a local kirana store wanted to sell online, it had to join a specific marketplace — and that marketplace set the rules, the fees, and controlled the customer relationship. Buyers were locked into specific apps; sellers were dependent on specific platforms.
ONDC defines a shared protocol. A seller can list through one app, and a buyer using a completely different app can find and purchase from that seller. The "network" is not owned by any single platform.
This matters most for:
- Small and medium sellers who can reach buyers across multiple buyer-facing apps without paying single-platform commissions or being subject to one platform's ranking algorithms.
- Buyers in smaller cities who gain access to a wider range of local and national sellers they could not previously reach through any single app.
- Service providers — auto-rickshaws, salons, couriers, and eventually many more — who can list through local apps or aggregators and be discoverable across the network.
The network is young and still growing. Coverage varies by city and product category. But the design principle — open, interoperable, with no single gatekeeper — is the same one that made UPI work.
How These Layers Connect
These five systems are not independent. They reinforce each other:
- Aadhaar-linked KYC makes it possible to open a bank account digitally, which is the prerequisite for UPI.
- A UPI-linked bank account generates a transaction history that can flow, with consent, through the Account Aggregator framework to a lender.
- DigiLocker stores the documents a lender needs to verify income and address.
- ONDC rides on top of UPI for payments, and will increasingly use AA-based verification for seller onboarding and buyer credit.
A first-generation migrant worker in a city can now open a bank account, receive salary digitally, build a credit history, access a small business loan, and sell goods online — entirely through their phone, using systems that were not commercially available to them a decade ago.
What This Means for Small Businesses
If you run a small business in India — a shop, a service, a food stall — the practical implications are:
- Payments: A QR code and a UPI ID are all you need to accept digital payments from any app.
- Formal credit: Your GST filing and bank cash flow, shared via Account Aggregator, can make you creditworthy to lenders who could not evaluate you before.
- Discoverability: Open networks like ONDC mean you do not have to choose just one platform and pay its full commission to reach online buyers.
Trying ONDC-Powered Discovery
ONDC is still being experienced mainly through apps that most people haven't heard of yet — because the buyer-facing interfaces are newer and more varied than the familiar big marketplaces. One way to explore it is through Bino, which lets you search for products and local services over WhatsApp using the ONDC network, without needing to install a new app. It is a small example of the same principle: an open rail, with different interfaces on top.
The infrastructure story of the last fifteen years in India is genuinely unusual — a government-built, openly accessible technology stack that has moved faster and reached more people than most private-sector alternatives elsewhere in the world. The next chapter is commerce. It is worth paying attention to.
Originally published on the Bino blog.
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