In this chapter, we have seen how you can manage, in an isomorphic way, the authentication of a user, covering the most popular cases like sign in, login, and authenticated and not authenticated requests. Almost all complex systems need to cover these use cases; that's why I think it's useful to cover them in this chapter and book.

In the next chapter, we will talk about testing and deployment. Testing is one of the most important topics of any mature application, no matter if it's web-based, terminal-based, or a console game. You must have a set of tests covering your application use cases, letting you develop with confidence and at a faster pace. We will then explore some concepts that you need to have in mind when preparing your application for production time and some online platforms where you can deploy your application in a simple and elastic way.

Enough, let's go!