Node.js is an open-source, cross-platform runtime environment for developing server-side Web applications. Node.js is not a JavaScript framework, but its applications are written in JavaScript and can be run within the Node.js runtime on a wide variety of platforms, including FreeBSD, IBM AIX, IBM i, IBM System z, Linux, Microsoft Windows, NonStop and OS X. Its work is hosted and supported by the Node.js Foundation, a collaborative project at the Linux Foundation.