Building web applications can be a rewarding experience. The satisfaction of reaching a broad set of potential users can trump the frustrating nights spent fine-tuning an application and fixing bugs. But some mobile users demand a more streamlined experience that only a native mobile app can provide.
Mobile browsers may experience performance issues in low-bandwidth situations, where HTML5 applications can only go so far with a heavy server-side backend. Enter Web API, with its RESTful endpoints, built with mobile-friendly server-side code.
In order to create a piece of software, years of wisdom tell us that we should build software with users in mind. Without use cases, its features are literally useless. By designing features around user stories, it makes sense to reveal public endpoints that relate directly to user actions. As a result, you will end up with a leaner web application that works for more users.
If you need more convincing, here's...