Unified Payments Interface, launched by NPCI on April 11, 2016, completed ten years of operation in 2026. Built on IMPS infrastructure and regulated under the Payment and Settlement Systems Act, 2007, UPI now processes over 18 billion transactions monthly, accounting for roughly 46% of global real-time payment volumes. It operates across 8 countries including Singapore, UAE, and France. The system connects 600-plus banks and supports features like UPI Lite, UPI 123PAY for feature phones, and credit-line-on-UPI.

UPI is a real-time, mobile-first interoperable payment system built on the Immediate Payment Service (IMPS) rails developed by NPCI. It uses a Virtual Payment Address (VPA) to abstract bank account details, enabling push and pull transactions on a 24×7×365 basis. The regulatory anchor is the Payment and Settlement Systems Act, 2007, under which RBI authorises payment system operators. NPCI, a not-for-profit entity set up jointly by RBI and IBA under the Companies Act, owns and operates UPI.

At its core, UPI works on a two-factor authentication model (device binding + UPI PIN) and is interoperable across third-party apps (PhonePe, GPay, Paytm, etc.) and bank apps. This interoperability, mandated by NPCI, is what separates UPI from closed-loop wallets.

Key structural milestones: UPI was launched April 11, 2016; UPI 2.0 added overdraft accounts and one-time mandates (2018); UPI Lite (offline, low-value transactions without UPI PIN up to ₹500, wallet limit ₹2,000) was introduced in 2022; UPI 123PAY for feature phones (IVR, missed-call, app-based) in 2022; and credit-line-on-UPI allowing pre-sanctioned credit lines from banks to be used via UPI was enabled in 2023. RBI has also set a market-cap rule: no single third-party app can exceed 30% of total UPI transaction volume, though the deadline has been extended multiple times. Globally, UPI linkages exist with PayNow (Singapore), PromptPay (Thailand), and several Gulf nations. India's share of roughly 46% of global real-time payment volume is a critical statistical anchor for exam purposes.