- 1. multiplexing protocol implemented on top of HTTP/2
- 2. serialization format via protobuf
For most companies, neither 1 or 2 is needed, but the side effect of 2 (of having structured schema) is good enough. This was the idea behind twrip - https://github.com/twitchtv/twirp - not sure whether this is still actively used / maintained, but it's protobuf as json over HTTP.