This document provides an overview of the Unified Payments Interface (UPI) system in India. UPI allows users to instantly transfer money between bank accounts using only a smartphone. It was developed by the National Payments Corporation of India to facilitate inter-bank transactions. Key features include not needing the recipient's bank details, being able to link multiple accounts to a single app, real-time payments, and increased convenience for bill splitting and purchases. Advantages include low fees, ease of use, and availability 24/7 from any account, while disadvantages include transaction limits, internet dependence, and potential delays.