As per spring 5:
WebClient is an interface representing the main entry point for performing web requests.
It has been created as a part of the Spring
According to the Java Doc the RestTemplate will be in maintenance mode. Spring team advise to use the WebClient if possible:
NOTE: As of 5.0, the non-blocking, reactive org.springframework.web.reactive.client.WebClient offers a modern alternative to the RestTemplate with efficient support for both sync and async, as well as streaming scenarios. The RestTemplate will be deprecated in a future version and will not have major new features added going forward.