[shepherdjerred]

Oh, I see. Yeah, you'd definitely need to be very careful in this case.

To be fair though, this is a general problem when clients and servers might not agree on data formats. You can still safely do what the author is describing since type checking occurs at compile-time and not runtime.

You would, of course, need to be sure your app handles whatever the API/db returns at runtime though. But, again, this is a general problem.