I see that the JSON middleware slurps, too: https://github.com/ring-clojure/ring-json/blob/master/src/ring/middleware/json.clj#L14

I guess that will conflict with me slurping first.

FWIW, I updated my gist with the final, working version: https://gist.github.com/ska2342/4567b02531ff611db6a1208ebd4316e6#file-gh-validation-clj