They wrote their own json parser which used strlen() all over the place, which is O(n), resulting in O(n^2) complexity for json parsing. The guy shimmed the fun

They wrote their own json parser which used strlen() all over the place, which is O(n), resulting in O(n^2) complexity for json parsing. The guy shimmed the function to return a cached response if it was called with the same string consecutively, which it was for parsing the JSON. The JSON contained the items in the real-money store btw.