Lowest level contract for reactive HTTP request handling that serves as a common denominator across different runtimes.

Higher-level, but still generic, building blocks for applications such as WebFilter, WebSession, ServerWebExchange, and others are available in the org.springframework.web.server package.

Application level programming models such as annotated controllers and functional handlers are available in the spring-webflux module.

Typically an HttpHandler represents an entire application with higher-level programming models bridged via org.springframework.web.server.adapter.WebHttpHandlerBuilder. Multiple applications at unique context paths can be plugged in with the help of the ContextPathCompositeHandler.