Many of the advantages we've just discussed apply to any single-page application, not just a Backbone one. This means that you can achieve many of those benefits even if you use one of Backbone's competing libraries, such as Ember or Angular. Whether you've considered using these frameworks or not, you're probably at least wondering, "Will Backbone provide me with everything I need to build my site, both now and in the future?"

The first thing to consider when answering this question is whether or not Backbone has an active community and will continue to be actively developed. Backbone users can feel safe in this regard: at the time of writing this book, Backbone's GitHub page had more than 1,500 watchers and more than 21,000 stars, beating its next closest competitor (Ember) by more than 400 watchers and 7,000 stars. Other frameworks such as CanJS and Google's Angular have even less interest on GitHub. While this certainly doesn't make Backbone better than those libraries, it shows the strength of its community and should provide you with the assurance that Backbone will be around for many years to come.

Another reason to feel confident when selecting Backbone is that it only tries to do a specific set of tasks, leaving everything else to external libraries. This means that if you find a better template system, dependency management tool, or any other library in the future, you can easily switch to using it. Other frameworks tightly couple things such as their template systems to their framework, leaving you with less options in the future.

However, perhaps the biggest indicator of Backbone's vitality is the companies that are already using it to accomplish amazing things. Companies as varied as USA Today, Pandora, Hulu, Gawker Media, AirBnB, Khan Academy, Groupon, and even Walmart use Backbone to create powerful web applications. If Backbone is powerful enough to support these major companies, it's almost certain to be powerful enough for your project.

There's one other company that uses Backbone, which is the company that I work for—Syapse. At Syapse, we've built a precision medicine data platform that helps hospitals receive genetic data in a structured format, pull patients' clinical data from a variety of internal health IT systems, and present this data together in an interactive web application. Through this interface, physicians see their patients' genetic and clinical data in context, enabling them to choose the most effective drugs possible tailored to a patient's own genetic profile.

Creating an application like Syapse did isn't easy, and with serious diseases such as cancer on the line, there's little room for error. However, using Backbone, Syapse has managed to grow from just one developer to a six-person client-side team with over 21,000 lines of code (not counting libraries) in just 3 years. Were it not for Backbone's ability to scale, there's simply no way we could have grown that quickly, at least without making major changes to our architecture along the way.

In short, while Backbone itself may be just under half a decade old, the real-world usage of the library has proven both its value and scalability. If your goal is to create a powerful and robust web application that a single developer can easily get off the ground but which can also grow and be supported by a full-sized team, you cannot go wrong with Backbone.