Express is a web application framework for Node.js, released as free and open-source software under the MIT License. It is designed for building web applications and APIs.
Progressive Web Apps (PWAs) are web apps built and enhanced with modern APIs to deliver enhanced capabilities, reliability, and installability while reaching anyone, anywhere, on any device, all with a single codebase.
Razorpay is a provider of an online payment gateway that allows businesses to accept, process, and disburse payments.
Unpkg is a content delivery network for everything on npm.