In this chapter, we started the development of our frontend, using the backend that we created in Chapter 4, Securing and Testing Your Backend. We defined the functionalities of the frontend and created a mock-up of the user interface. We started frontend development with an unsecured version of the backend, therefore, we made some modifications to our Spring Security configuration class. We also created the React app that we are going to use during development.  In the next chapter, we will start to add CRUD functionalities to our frontend.