Node.js is an open source, cross-platform runtime environment for server-side and networking applications. Node.js applications are written in JavaScript, and can be run within the Node.js runtime on OS X, Microsoft Windows, Linux, FreeBSD, and IBM i. Node.js provides an event-driven architecture and a non-blocking I/O API that optimizes an application’s throughput and scalability. These technologies are commonly used for real-time web applications. Node.js uses the Google V8 JavaScript engine to execute code, and a large percentage of the basic modules are written in JavaScript. Node.js contains a built-in library to allow applications to act as a Web server without software such as Apache HTTP Server or IIS. Node.js is gaining adoption as a server-side platform and is used by Microsoft, Yahoo!, Walmart, Groupon, SAP, LinkedIn, Rakuten, PayPal, Voxer, and GoDaddy.