# Copay NW.js NW.js (also know as node-webkit) is an app runtime based on `Chromium` and `node.js`. To build desktop native application, Copay uses NW.js. ## Building Copay for OSX, Linux and Windows versions **Requirements** - Install NW.js in your system from [nw.js](http://nwjs.io/) **Builder** - Try `grunt desktop` (*)