Node.js is a software platform for scalable server-side and networking applications. Node.js applications are written in JavaScript. All of the popular server operating systems are supported, including Windows and Linux.
Node.js applications are designed to maximize throughput and efficiency, using non-blocking I/O and asynchronous events. Node.js applications run single-threaded, although Node.js uses multiple threads for file and network events. Node.js is commonly used for real time applications due to its asynchronous nature, allowing applications to display information faster for users without the need for refreshing.
Node.js is a runtime environment combined with libraries for common web application requirements. Internally, it 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 asynchronous I/O library for file, socket and HTTP communication. The HTTP and socket support allows Node.js to act as a web server without additional web server software such as Apache.
Node.js was created by Ryan Dahl starting in 2009. Its development and maintenance is sponsored by Joyent.Dahl was inspired to create Node.js after seeing a file upload progress bar on Flickr. The browser did not know how much of the file had been uploaded and had to query the web server. Dahl wanted an easier way. Ruby's Mongrel web server was another source of inspiration for Dahl.
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