Checking if user is logged in cross domain (API question)

[envexlabs]

Hey,

 

I'm currently writing an api for one of our sites that displays a list of products and then allows users to favorite those products.

 

The main site is:

 

Store.com (this holds all the stores information as well as the shoppers login information)

 

and the products are generated on

 

Shelf.com

 

So when a user comes to shelf.com, i need them to be able to get the login information from store.com and set variables to allow them to favorite these products.

 

The API right now uses cURL to grab files off the store.com server to display the products. This is my first attempt at an api and i'm pretty sure i'm doing everything wrong, but any help would be greatly appreciated.

 

Thanks,

 

envex