There are 2 inputs you might have and you can also convert between them.
example: [{"":{"...
The pd.DataFrame() needs a listOfDictionaries as input.
example: '{"":{"...
If you have jsonStr, you need an extra step to listOfDictionaries first. This is obvious as it is generated like:
jsonStr = json.dumps(listOfDictionaries)
Thus, switch back from jsonStr to listOfDictionaries first:
listOfDictionaries = json.loads(jsonStr)