A few years ago I thought that using RPC is archaic and bad design. Now with more experience I think that RPC is actually very useful for real world applications. For simple CRUD REST is wonderful, it takes effort, but you can model a lot of things with resources. But when it comes to performance and more conplex data collection it's hard to scale. Now that we have the need for batch operation we ended up with a mix of rest and roll-your-own RPC throught POST endpoint. It led me to think that maybe we should use REST only on external APIs for easy consumption and go full RPC between our services. Also JSON is so verbose for sending over the network. Oh and compressing it over HTTPS is a no-go, because of BREACH and CRIME.