Just as a basic question in Magento 2. In Magento U tutorials, it says:
In Magento 2 Modules only communicate through API
One module in not aware of the internals of another, so the implementation can change.
Modules can be disabled or deployed on separate servers.
I don't get what it means by "Magento 2 modules only communicate through API" ? If I want to load products, how we are using APIs without knowing?
I need a little bit explanation about interface vs. API interface vs. Web API. Is there any difference ? How?