If we move away from a specific gRPC implementation — what is RPC as an approach and what problem does it solve?

RPC (Remote Procedure Call) is an approach to interaction between programs, where one program calls a function or procedure that is physically executed in another program or on a remote server, as if it were a local call.

The problem that RPC solves is the simplification of distributed computing and communication between different system components. Instead of manually dealing with network protocols, serialization, and deserialization of data, the developer works with remote calls as if they were regular functions, which increases convenience and reduces the complexity of developing distributed applications.

Thus, RPC abstracts the details of network interaction, allowing the creation of distributed systems with a cleaner and more understandable architecture.