Sure, calling internal API is sensible. I am not saying it needs to be public API. But you probably can't avoid some serialization (be it REST, GQL, GRPC), the

Sure, calling internal API is sensible. I am not saying it needs to be public API. But you probably can't avoid some serialization (be it REST, GQL, GRPC), the service that owns the data can be different than the one serving the html. I am not saying everybody needs to do microservices but my experience with monolith is bad. You want at least "some" services and the html-serving service shouldn't usually own the data. User data belongs to user service, report/analytics data to analytics service etc. Just from the security point of view, the stuff facing internet should have minimum rights to read/write anything. Definitely not direct function-calling or db access.