I love DjDT, but it doesn't detect duplicate queries and can't be used for non-HTML responses (eg JSON APIs).
https://gist.github.com/leetrout/ab136dbfb97f8ee1d309
;)
Edit: After install appending `?dbg=1` to a JSON returning view will inject the html wrapper. e.g. http://foo.com/bar.json?dbg=1