In this chapter, we improved the RESTful API in many ways. We added user friendly error messages when resources aren't unique. We tested how to update single or multiple fields with the PATCH method and we created our own generic pagination class.

Then, we started working with authentication and permissions. We added a user model and we updated the database. We made many changes in the different pieces of code to achieve a specific security goal and we took advantage of Flask-HTTPAuth and passlib to use HTTP authentication in our API.

Now that we have built an improved a complex API that uses pagination and authentication, we will use additional abstractions included in the framework and we will code, execute, and improve unit test, which is what we are going to discuss in the next chapter.