I can see you have switched away from the API you were using, so I guess it doesn’t matter much anymore, however. The API really should not be sending strings with escaped single quotes (it’s invalid as far as I know).
\' is never a valid escape sequence in a JSON string. It doesn’t need to be, because JSON strings are always double-quoted.
Here is another one I got from the API (this will fail validation), so it’s probably better not to use it anyway.
"quoteText": "There is nothing in a caterpillar that tells you it\'s going to be a butterfly.",
"quoteAuthor": "Buckminster Fuller",