What is Node.js?
Node.js is a JavaScript runtime built on Chrome's V8 engine that lets JavaScript run outside the browser — on servers, in build tools, and in CLIs. Its event-driven, non-blocking I/O model makes it well suited to handling many concurrent network connections with a single thread.
Example
node server.js runs a JavaScript file as a standalone server process.
Related tool
Try it on ToolSphere — runs entirely in your browser, nothing is uploaded to a server.