Agreed! For the user facing bit, I consider REST or some other form of HTTP-based a given. As a (human) user, I want to base my communication on commands and qu

Agreed! For the user facing bit, I consider REST or some other form of HTTP-based a given. As a (human) user, I want to base my communication on commands and queries, and do want responses! But the services that generate those responses should not have runtime dependencies on other services. Those backend services should interoperate in an event-driven way.