I am using the webclient from spring webflux, like this :
WebClient.create() .post() .uri(url) .syncBody(body) .a
Note that as of writing this, 5xx errors no longer result in an exception from the underlying Netty layer. See https://github.com/spring-projects/spring-framework/commit/b0ab84657b712aac59951420f4e9d696c3d84ba2