Schema for REST API?

Question

I am wondering if is there any schema for the REST API (json)? Or any detailed documentation on the fields?

When fetching data for an issue, I can see fields with a primitive type value, or fields with an object value. How is it decided if a field has a primitive value or an object value? Is this project specific or globally the same?

For example summary has a primitive type, while type has not. Is this global? Can we trust that it is the same on every Jira server?

Warren_mz9b4z · Accepted Answer

To answer your later questions first, the type is not project specific and it is global i.e. what you get on one server / instance will be the same as any other.

As to your first question, I have seen a schema of sorts, but can't remember where it is. Your easiest way is to run a query (but limit it to 1 issue i.e. pass in a parameter of jql=key=XXX-123) and don't specify which fields to return. View the returned json in a json formatter and you can then build up a list of what types there are and how to reference them