Google Content API for Shopping

The Google Content API for Shopping is a set of formats and protocols used to exchange product information between online merchants and Google for the purpose of getting the products into the Google Shopping service. The main format used is Atom, an XML-based format, which is used with some custom Google namespaces. HTTP requests are used to send and receive the data. Some protocols can also use JSON data.

Links

 * Google's site about Content API for Shopping
 * Products Feed Specification
 * Google Data API basics