Today, I registered for an eBay Development account. The eBay Developers Homepage provides support, documentation, code samples, API keys, affiliate programs, forum, sandbox, tools, release notes and system announcements.
I started using the shopping API (view guide) which is optimized for response size, speed and usability. This API allows to search for eBay items, products and reviews, user info, and popular items and searches. You are able to retrieve public eBay data in a buyer-friendly view, for easy consumption by buyer-focused applications. The call reference (version 613) of the eBay shopping API is available on the following link. The call “FindItemsAdvanced” is the most useful and enables you to search for items on eBay based on many possible input fields and filters. Detailed informations are available here.