In addition to what my sibling comment says about "sanitizing" external data – which I wholeheartedly agree with – the "open API front-facing the internet" is i

In addition to what my sibling comment says about "sanitizing" external data – which I wholeheartedly agree with – the "open API front-facing the internet" is in the process of changing, if you're talking about normal websites. gRPC-web isn't quite feature complete relative to normal gRPC, but it is getting pretty close, and the gains of avoiding JSON (de-)serialization would be big. I think once the protobuf story has a complete chapter for the front-end, bigger engineering orgs will roll it out much like they're rolling out typescript today. If you're talking about actual developer/public-facing APIs, those will probably remain in JSON land for a while.