Spring Security can be used to secure REST APIs. This chapter begins with the introduction of some of the important concepts in regard to REST and the JWT.

The chapter then introduces OAuth concepts and by using hands-on coding examples, explains simple and advanced REST API security utilizing the Spring Security and Spring Boot modules in the Spring Framework.

We will be using the OAuth protocol in our examples to secure exposed REST API's utilizing Spring Security features to the fullest. We will be using the JWT to exchange claims between the server and client.

In this chapter, we will cover the following concepts:

• Modern application architecture
• Reactive REST API
• Simple REST API security
• Advanced REST API security
• Spring Security OAuth project
• OAuth2 and Spring WebFlux
• Spring Boot and OAuth2