Node.js (Node) is an I/O environment built on top of Google Chrome's JavaScript runtime — essentially, a server-side implementation of JavaScript. Node's asynchronous, event-driven I/O model makes it easy for developers with JavaScript knowledge to build high-performing, scalable, and highly concurrent web applications rapidly and run them in the cloud. This knowledge path starts with Node.js basics and takes you beyond them to using Node and supporting technologies to build an application, test it, and deploy it on a platform-as-a service.