Servers supporting Spring WebFlux

Spring WebFlux supports 

1. Servlet 3.1+ containers such as Tomcat, Jetty.

2. Non-Servlet runtime such as Netty and Undertow.

In Spring boot application, the starter uses Netty by default. We can easily switch to other servers such as Tomcat, Jetty, or Undertow by changing the Maven or Gradle dependencies.  

Reference: