eBay has some very cool functionality that allows application programmers to make API calls on a user’s behalf without using their site credentials. I decided to investigate the eBay API a bit and wrote a function that allows web developers to print the items listed in an eBay buyer’s My eBay section on third party web pages. Feel free to check out the code.

The eBay Developer Program has a guide to help developers begin using the API. You can make all kinds of unauthenticated function calls to the API, like listing search results, without using eBay’s Auth and Auth (Authentication and Authorization) system. But to make calls on behalf of a particular user, you will need to generate an auth token. This can be done using eBay’s Authentication Token Tool.

Essentially, this process works by entering an eBay user’s site crentials in the token generator and eBay returns a cryptographic token. This token can then be passed along with the API function calls to authenticate the caller without including the user’s login and password.

The function I wrote is essentially a wrapper to the API call GetMyeBayBuying. Calling my function, printMyEbay, will print the auctions that a user is a) watching, b) bidding on, and c) has won.