What is the difference between an UPI and an UPI gateway?

UPI (Unified Payments Interface) is an instant, real-time payment system that allows direct bank-to-bank transfers via a UPI ID or QR code. A Payment Gateway is a platform that facilitates online transactions, often offering UPI as one of many payment options (like credit/debit cards). While direct UPI is simpler for immediate, in-person payments, a payment gateway offers a unified checkout experience, automated reconciliation for businesses, and generally higher security when processing multiple payment types online.