Dependency Injection (DI) is a design pattern to change definition by substituting object without changing code for the application. The most popular DI type is to construct classes based on certain interface and pass actual object on constructor level. What are we trying to do? We will be looking into a way to achieve dependency injection through XML configuration based on build selection . The implemented classes derived through interface will get switched based on build selection. Where to use it? I really hate making dependencies with something specific which can be changed later on. In my case, Azure environment. I believe Azure is more like a platform where we can host the application rather then integrating the application with Azure. What if client decided to switch to other hosting environment, in that case we got to change every piece of code wherever Azure SDKs are referred. The above one is merely an example. We can use this approach on many other item as well.