A JSON string must be double-quoted, according to the specs, so you don't need to escape '.
If you have to use special character in your JSON string, you can escape it using character.
See this list of special character used in JSON :
Backspace (ascii code 08)
f Form feed (ascii code 0C)
New line
Carriage return
Tab
" Double quote
Backslash character
For new readers, always use a double quotes for your json strings.