I tried to find any mention of handling of compression in new Java HTTP Client but failed. Is there a built-in configuration to handle for e.g. gzip or de
No, gzip/deflate compression are not handled by default. You would have to implement that in your application code if you need it - e.g. by providing a customized BodySubscriber to handle it. Alternatively - you may want to have a look at whether some of the reactive stream libraries out there offer such a feature, in which case you might be able to pipe that in by using one of the BodyHandlers.fromSubscriber(Flow.Subscriber super List or BodyHandlers.ofPublisher() methods.