Razorpay is a popular payment gateway solution in India that provides APIs and SDKs for integrating payments into mobile apps. This document discusses how to integrate Razorpay payments into an iOS app built with Swift. It involves installing the Razorpay pod, setting up a basic UI, importing Razorpay, initializing it with the public key, handling payment callbacks, and calling the open method to launch the Razorpay payment screen when a user clicks pay. Possible error codes for failed transactions are also provided. The complete demo project code is available on GitHub.