Getting user’s home/ship-to country is important for the following:
If you have a two character country code (ISO 3166-1 alpha-2) already, (for example, “US”), then feel free to skip this section.
It’s incredibly important that this happens from the client. So if you are building a website, you’ll want this JSONP request to happen on the client via AJAX. Maybe use our gooten-js library?