I used links but I'm gonna rewrite this code to simply pass IDs. The reason is simple: I need additional configuration for my server to know its hostname and I don't want to do that. May be my server even have few different hostnames for different clients? So I must parse client request and extract Hostname? But it's served via reverse-proxy, so I must do some complex configurations to pass this information. So many issues. But client knows perfectly well which server he's talking to, so he can just append server-base and id. Yes, client must know about its structure, but it's nonsense that client can somehow learn something. I'll code that anyway.

May be it makes sense when you're writing an API and some different person writes a client and she's so shy that she don't want to even ask you. Yeah, she can inspect answer and find out that this seems like a link to query further. I never was in that situation, I was always building all software myself, so for me this does not make sense.