Hi Andreev,
Welcome to crystal :-)
There is no http2 support yet. But as
https://github.com/manastech/crystal/pull/2009#issuecomment-171851780 there were some progress towards future support.
There is no protobuf support in the std lib. There is a nice json utils that allows you to declare the expected schema and serialize/deserialize data according to it.
There was a shard with msgpack support in case a binary format is needed.
On a personal taste if a gRPC is to be supported something inspired in ECR/process would allow to generate efficient code during compilation that will generate/parse binary/text messages without parsing the .proto file that defines the schema.
I hope is no discouraging that both answers are "no" in the end. But at the same time, it a space for nice contributions if is the are you are interested in.
Regards & welcome again,
Brian J. Cardiff