[basicallydan]

> I love the separation of concerns that is possible with JS apps - you can have one team working on the API and one on the interface and the only place they really need to communicate is in the API documentation.

Yeah, me too. Apart from the actual, observable benefits you mentioned, I just find something really satisfying about the separation. Fewer hacks, easier to modify things.

I think the rise in the popularity of doing things this way is largely thanks to the increase in popularity of test-driven development. Creating a client app without an API is so easy given all the tools available for mocking or faking APIs, and creating a standalone API is easy given that most of the time, you're just testing the JSON or XML output of a bunch of functions.