At its core, Backbone is just a JavaScript library, and as such, it doesn't add any new performance challenges that weren't already in JavaScript to begin with. In fact, the creators of Backbone have taken great care to make the library perform well, and in performance comparisons with rival libraries, Backbone typically comes out ahead, if not on top.

However, while Backbone itself doesn't create performance issues, it does enable entirely new ways of creating web applications, and because such applications can be far more complex than traditional websites, a whole new realm of potential performance issues is exposed. In this chapter, we will explore these issues, as well as their underlying technical details, and address ways to avoid or mitigate them.