It’s possible to structure the question to fit 30-45min. It’ll be pretty clear what level and experience a person has in doing api’s. If the json response is already laid out, parsing json can be an independent task from the network call. The point of the interview is to see if the person can reasonably code it, it doesn’t have to be production grade.
leetcode interviews do not test if a person can reasonably code. they expect people to give a specific optimal solution to a specific question which you can only provide if you have solved the question before, in the way it is expected, within max 2-3 minutes. the process is broken.
the moment you ask a candidate to build something you could use in your codebase you should pay them.