In strongly typed languages, there are serialization/deserialization libraries that don't require you to type the entire JSON object - just the fields you care about.
The real benefit of using a well typed language here is that you only need to parse the data once at this point, after that the type system makes sure the data is of correct format everywhere else in your codebase.
It is a very good library if you control both sides of the communication, and have fit for purpose interfaces. Otherwise, you are better with any lower level library.
Besides, what is it with the strictness of Haskell JSON libraries? There's nothing that will even accept Window's BOM.
With Aeson, You always have the option work with a map directly and pull out properties by name.
That is also especially useful when you can't predict what keys or shape the data will have
But it's a very complex library. It may not show at your code interface, but that complexity is there at the documentation and type errors. It is also famous for generating bad runtime messages. There is even another library for fixing this, at the cost of even more complexity.
If you fall outside of its optimum usage scenario, it won't afford you more functionality than a low level parser, so you are much better saving that complexity and going with the parser.
OP was complaining that it's hard to type some kinds of payloads.
Sure you could write a custom parser for it.
With fromJSON in fact this is what you write. Maybe if you've only been driving Json instances generically, you never actually written a fromJSON instance in Aeson? I only use generic deriving in the simplest cases.. otherwise just write the fromJSON instance parser
My point was that you can defer parsing up front and just return a map of you don't want deal with the shape.
But sure you could write a custom parser as well, that falls more into the typed philosophy though than what js folks are used to