gRPC
gRPC uses a binary format to encode data, which is much more Performant than many other Message Protocols.
The fact that it is binary also implies that it is much harder to consume, but this is not the case. The message format can be declared using Proto, and there are implementations for almost all conceivable Programming Languages to use that definition to generate code to serialize and deserialize the message.
That leaves the downside that one gRPC cannot be read messages in transit, and see its content, where both XML and JSON would be humanly readable to some extend.
Another reason why gRPC is much faster than most other Message Protocols, is that it is not based on HTML. HTML adds overhead to communication that makes it easy to understand, but is overhead nevertheless.