Backbone.js is a JavaScript library with a RESTful JSON interface and is based on the model – view – presenter (MVP) application design paradigm. Backbone is known for being lightweight, as its only dependency is on one JavaScript library, Underscore.js. It is designed for developing single-page web applications, and for keeping various parts of web applications (e.g. multiple clients and the server) synchronized. Backbone was created by Jeremy ashkenas, who is also known for CoffeeScript.