Using Haskell to Auto Derive JSON Desortization

The approach that I've used in Elm, and I know you can do this in Haskell, but there is a sort of a question of how much it's done. It's certainly quite popular to auto derive your JSON desortization in Haskell and basically say like, here's my data structure. And if it doesn't look exactly like that, then give me an error. But I have seen a middle ground, as he would say, in like what Elm does. So in Elm, you specify theseJSON decoders. The type checker is you're all in the known knowns land that the type checker could be very helpful.