Sorry, Arun, RPCs are an archaic technology that I used back in the 70s when it was all we had. Software engineering has come a long way since then.

We've learned to avoid tight coupling of components for many compelling reasons. It is a fundamental principle of microservice architecture. It is painful watching developers making the same mistakes again for the same old reasons.

JSON didn't exist when Roy Fielding wrote his dissertation on REST, but it is a useful "self-defining" message syntax. Protocol buffers are anything but self-defining and require a complex system for distributed schema management to work at all. That may be justifiable when data compression is the overriding concern, but it makes loosely-coupled microservices impossible to implement.

A properly designed RESTful solution is a far better match for the implementation of a microservice architecture.

https://medium.com/nerd-for-tech/microservice-architecture-622e4148f1