Vue.Js is a progressive framework for building user interfaces. Vue.js is a lightweight counterpart of Angular.js and it was an alternative to it. The core library is focused on the view layer only and is easy to pick up and integrate with other libraries or existing projects. Vue is also perfectly capable of powering sophisticated Single-Page Applications. One of the best feature of Vue.Js it is lightweight just 18Kb after zipped. Hence it provides much need speed and accuracy. It can be used to build both single page and Complex Web applications. Vue can be used as a library and fully-fledged framework.
BackboneJS: Backbone.js gives structure to web 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 API over a RESTful JSON interface.