The ASP.NET Core routing system can be extended and used to cover a lot of use cases. In general, it provides all the necessary functionalities out of the box. It is essential to understand that conventional routing is generally used by web applications, while web services routing is usually achieved by applying the attribute routing. This chapter described how to deal with these two approaches,  how to use the out-of-box constraints provided by ASP.NET Core and how to implement our custom routing constraints.  In the next chapter, we will look at how to deal with the filter pipeline of ASP.NET Core and in which way they differ from the implementation of the middleware classes.