In this chapter, we learned that WebFlux is an efficient replacement for the good old Web MVC framework. We also learned that WebFlux uses the same techniques for request handler declarations (using the well-known @RestController and @Controller). In addition to the standard handler declaration, WebFlux introduces a lightweight, functional endpoint declaration using RouterFunction. For a long time, modern reactive web servers, such as Netty, and non-blocking Undertow features were unavailable to users of the Spring Framework. With the WebFlux web framework, these technologies have become available using the same, familiar API. Since WebFlux is based on asynchronous non-blocking communication, this framework depends on Reactor 3, which is the core component of the module.