The Unified Payments Interface (UPI) is an instant payment system and protocol developed by the National Payments Corporation of India (NPCI), which is regulated by the Reserve Bank of India (RBI). It was officially introduced on April 11, 2016, to solve the problem of a fragmented digital payment ecosystem and promote financial inclusion by simplifying transactions. UPI allows for real-time, inter-bank peer-to-peer (P2P) and person-to-merchant (P2M) fund transfers using a mobile device.
The mechanism works by integrating multiple bank accounts into a single mobile application, running as an open-source Application Programming Interface (API) on top of the Immediate Payment Service (IMPS) platform. A user initiates a payment by entering the recipient's unique Virtual Payment Address (VPA), also known as a UPI ID, or by scanning a QR code, eliminating the need for bank account numbers and IFSC codes. The transaction is secured by Two-Factor Authentication (2FA), requiring the user to authorize the payment with a UPI PIN. The request is routed through the NPCI's UPI switch, which validates the PIN and balance with the sender's bank before crediting the amount to the beneficiary's account in real-time.
UPI is a core component of the broader India Stack framework and is connected to institutions like the RBI and NPCI, which issue operational guidelines under the Payment and Settlement Systems Act, 2007. Recent changes include the NPCI's operational guidelines, effective from August 2025, which introduced technical and operational limits, such as capping daily balance checks and regulating the processing window for AutoPay mandates to enhance system stability. Furthermore, the RBI's "Authentication Mechanisms for Digital Payment Transactions Directions, 2025" mandates that from April 1, 2026, all domestic digital payments, including UPI, must use two authentication factors, with at least one being dynamic, to strengthen security. The baseline daily transaction limit for most transfers remains ₹1 lakh.