How to implement communication between individual application modules?

Question

Software design

The task is to implement a web service, to which various clients will subsequently connect to receive and process information.

According to the structure, a certain "main router" (R) is planned, to which clients will access via API (private). Also, additional application modules will be located on separate servers: catalog (K), statistics (S), neural network (N).

Clients can be: browser applications, mobile applications, self-hosted sites, etc. Therefore, REST API will be used to communicate with the main router R.

Question: how to organize the interaction between additional modules K, S, N and the main router R? Also via the RESP API? Or are there more suitable methods of interaction (since no external access, permanent authorizations, etc. are needed)?

Answer 1

Can be implemented via GRPC