EcommerceBytes-Update, Number 150 - September 04, 2005 - ISSN 1528-6703     5 of 8

Auction Software FAQ: What is the eBay API?

By Andy Geldman

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In this column, I will answer some common questions about software for online auction users. Some of these questions are ones I have been frequently asked, while others address areas that are not well understood, or have myths to dispel. If you have a question you would like to see answered here, please contact me at the email address below.

Today's question is, "What is the eBay API?"

Many eBay users will have heard of the eBay API, but few know what it really is or why it matters to them. Don't let the three-letter-acronym confuse you: an API is just a defined way for one program to access another program. In this context, "program" includes websites. So, the eBay API is eBay's official way of allowing other programs and websites to communicate with them and carry out tasks on behalf of users.

Most of the day-to-day functions you carry out on eBay can be done via the API, including searching, listing, dealing with disputes, and so on. Programs that use the API are able to streamline and automate these tasks without the user needing to visit the eBay site.

Some eBay functions are not exposed through the API, including bidding and registering a new user. Because bidding is not available, sniping programs do not work through the eBay API - it is of no use to them.

Those who want to develop an application that uses the API must register with the eBay Developers Program and submit their programs for certification by eBay. They pay an annual membership, a certification fee, and a small access fee every time they use the API.

The usage fee may seem very low (less than 3 dollars for 1,000 "calls") but consider that one call is incurred for adding a dispute, making a second-chance offer, submitting feedback, accessing My Messages and so on. (Listing and re-listing do not count towards these calls, but eBay charges listing fees for that instead.) This usage cost is one reason why most API developers charge users a fee based on sales volume. Ongoing development, customer support, and hosting fees also play a part.

Developers use the API because it is officially supported and offers a reasonably stable and efficient way for them to interact with eBay. On the downside, a considerable investment is required to create a certified application, and development must be continuous to keep up with changes and new functionality. They also have to pay the access fees generated by customers as they use their product.

The eBay API matters to users because it enables the development of programs with extensive and reliable access to eBay. You should expect API-based applications to work smoothly with eBay (though quality varies) and, normally, to be charged higher fees the more you use the service. Non-API applications are more likely to go wrong, but can have lower fees. Look for the "eBay Compatible Program" graphic or the older "eBay Certified Developer" logo to determine if a developer uses the API.


eBay Developers Program

API Logo Examples

eBay Developers Program blog

About the author:

Andy Geldman is a freelance ecommerce and IT consultant, and webmaster of Web Retailer, a guide to eBay software and services Andy lives in London, England and can be emailed at andy.geldman @

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