Where to get extensive response json for /rest/api/2/search?

I am automating jira api /rest/api/2/search in order to have defects extracted. Looking for a extensive response json format which I can use in my code. It seems that the one I get out of my api requests always has something short. Every other search criteria would have new fields in the responses. Also jira is always customized to requirements. So this json has to cater those changes as well. Can someone advise please?