JSONP, or JSON with Padding, is actually JSON but it is set up differently compared to traditional JSON files. JSONP is a workaround for web cross-browser scripting. Some web services can serve up JSONP rather than pure JSON JavaScript files. The issue with that is JSONP isn't compatible with many JSON Python-based parsers including one covered here, so you will want to avoid JSONP style JSON whenever possible.

So how can we spot JSONP files; do they have a different extension? No, it's simply a wrapper for JSON data; here's an example without JSONP:

/*
 *Regular JSON
 */
{ authorname: 'Chad Adams' }

The same example with JSONP:

/*
 * JSONP
 */
callback({ authorname: 'Chad Adams' });

Notice we wrapped our JSON data with a function wrapper, or a callback. Typically, this is what breaks in our parsers and is a giveaway that this is a JSONP-formatted JSON file. In JavaScript, we can even call it in code like this:

/*
 * Using JSONP in JavaScript
 */
callback = function (data) {
    alert(data.authorname);
};