You don't need to compile the protobufs. The alternative, for all serialization formats, is to either load the schema dynamically, or write the handling logic

You don't need to compile the protobufs. The alternative, for all serialization formats, is to either load the schema dynamically, or write the handling logic manually yourself (or write your own generator/compiler). gRPC supports HTTPv1 and can be mapped to a RESTful API (e.g. https://google.aip.dev/131 https://google.aip.dev/131).