There have been some great comments on this thread already and it’s making me think (which is always good!). I’m unsure if I should even be exposing IDs on this service, since they’re only really internal references and the service provides hypermedia to get to related items.

So it’s back to the proverbial drawing board for now, while I think about the use cases and what data would be useful. I think the other numeric fields probably do want to be numbers, but as Paul says, there’s the question about whether the automatic conversion is helpful.