Backbone.js is described as 'Backbone supplies structure to JavaScript-heavy applications by providing models with key-value binding and custom events, collections with a rich API of enumerable functions, views with declarative event handling, and connects it all to your existing application over a RESTful' and is a javascript framework in the development category. There are more than 50 alternatives to Backbone.js, not only websites but also apps for a variety of platforms, including Windows, Linux, Mac and Self-Hosted apps. The best Backbone.js alternative is Vue.js, which is both free and Open Source. Other great sites and apps similar to Backbone.js are Angular, React, Svelte and Vite.