[noctune]

You might be interested in https://connectrpc.com/. It's basically what you describe, though it's not clear to me how well supported it is.

[morshu9001]

Yeah that one looked good. I don't remember why I didn't use it that time, maybe just felt it was easy enough to DIY that I didn't feel like using another dep (given that I already knew express and proto in isolation). The thing is, Google themselves had to lead the way on this if they wanted protobuf to be mainstream like JSON.