correct use of @id vs url

Could I check on the correct use of @ld, particularly with APIs (as opposed
to embedded data in webpages, etc)?

My assumption is @id is intended to represent a IRI for an API object. So
if I call an API and get a list of objects, if @id is present in each
object, it should be an IRI of just that object in the API.

What I'm wondering is what is the best way to define a JSON value of a URL
to a webpage of the object, if the object has a webpage separate from the
API? Would "url" be the most logical option? I ask because many examples in
the JSON-LD spec and elsewhere often use @id for something like object's
webpage.

Also is there a convention for representing links to other canonical
representations of a thing elsewhere on the web, e.g. Wikipedia pages?

Many thanks,

Paul