Web services have served as a topic of interest for IT professionals since at least 2001, and yet there have been few examples of significant, successful deployment. With this in mind, developers and IT decision makers should be aware of the major, business-defining role of eBay's successful Web service deployment. With roughly a billion Web service requests served a month, eBay has demonstrated clear leadership in the real world deployment of Web services.

This article shows how eBay has been able to use Web services to dramatically grow both acquisition and third-party development efforts, transforming a Web site into a Web platform. It will examine the business benefits of Web services for eBay, its partners, and independent developers, and describe eBay's efforts to support this growing community. Finally, it will describe the future direction of eBay's Web service implementation.

Business Advantage of Web Services
How long does it take a business to put a product up for sale? How many people view that product? How long does it take to close the order after placement? Simply put, the eBay Web services platform is an integration engine that enables a business to dramatically improve all of these metrics.

eBay's Web service platform affords a proven, real-time integration opportunity for several different types of business. Most obviously, businesses that have grown beyond an occasional listing can use the eBay Web service platform to dramatically decrease the overall costs associated with managing inventory and working with eBay. This usage of the eBay platform enables integration and automation.

By using eBay Web services, businesses can build integration directly into their existing channel infrastructure for moving products. For example, a business may wish to leverage an existing inventory system to automatically generate eBay auction listings for products that have been sitting idle for ninety days. By integrating with eBay's Web services, an analyst can generate listings for these products with a single click. Similarly, integration with eBay Web services could allow for automatic notification of a successful closed integration with a business's fulfillment center, or trigger a customer satisfaction system 30 days after an auction has closed.

In the integration and automation model, Web services provides a highly efficient mechanism for improving the execution of business processes. Businesses can dramatically reduce the time to list and fulfill auction listings, increasing the rate of return.

This usage of eBay's Web services is in broad deployment today. eBay has found that sellers using Web service-enabled software applications generate an average of 595 new listings and $10,202 in GMS (gross merchandise sales, the value of goods sold) per minute on eBay. In addition, eBay sellers that transition from entering information by hand via the HTML forms to a Web service-enabled selling application typically report a listing volume improvement of over 60% within 6 months.

One additional side benefit of an organization looking to build on the eBay Web services platform - it gives an IT organization a chance to work with a successful, broadly deployed Web service platform, building experience in an arena that increasingly serves as a model for future solution development. By examining eBay's best practices, a savvy business can transfer knowledge into an existing IT organization.

Growth Through Acquisition
Web service-based integration is not limited to organizations outside of eBay. For example, eBay recently acquired www.mobile.de, the largest provider of automotive classified in Germany. The engineer assigned to integrate with eBay's Web services platform was able to build a working prototype of integration over a weekend.

The most dramatic example of this integration is PayPal. Acquired in October, 2002, PayPal can be considered the most significant and successful of all of the eBay Web service integrations. Of eBay's billion-plus Web service requests served monthly, roughly 40% serve PayPal.

PayPal Web Services
PayPal, in turn, has also invested heavily in a developer framework and Web services. Part of its merchant tools, PayPal Web services offers four informational and transactional APIs: TransactionSearch, GetTransactionDetails, RefundTransaction, and MassPay. These APIs enable developers to create payment applications that integrate with the PayPal platform. One additional interesting component, Instant Payment Notification (IPN), allows real-time integration of the PayPal payment processing system with a third-party application. For example, a developer can use IPN to respond to an incoming payment by e-mailing a registration code to an end-user and sending a fax to a fulfillment partner.

PayPal has grown in a similar fashion to eBay, from simple interfaces based on HTTPS, to the recent addition of SOAP and WSDL-based Web services. PayPal has recently added a test environment called the PayPal Sandbox, which is very similar to the eBay Sandbox. In addition, PayPal Developer Central offers information about how to set up developer certificates, get started with PayPal APIs, and access developer forums for discussion and questions. Given the challenges inherent in building a secure system for working with financial transactions over the Internet, PayPal's advances in the Web services arena represent a significant step forward for e-commerce.

As eBay continues to grow and acquire new entities, the Web services framework serves as an important strategic solution.

For more information see www.paypal.com/pdn.

Conclusion
"A platform is something that other people build on top of. Hundreds of thousands of people have built successful businesses on eBay. Millions have built relationships with others over shared areas of interest. eBay has been a platform long before we had an official Platform or Developer program. You know you're an effective platform when someone builds something you never predicted." - Pierre Omidyar, eBay founder and chairman

eBay's need for Web services grew out of a need to grow the company while retaining the flexibility for others to integrate and innovate. From there, Web services have grown to serve an important strategic role in the growth of the company. By focusing on the pragmatic, critical needs of the company, partners, and users, eBay has become a silent giant of the Web services world.

Through Web services, eBay has been able to transform itself from a popular Web site into a Web platform. Through the use of core technologies such as XML, HTTP, SOAP, and WSDL, eBay has been able to provide highly scalable, well-performing Web services. The business benefits are real today, and are expected to serve as a critical engine for growth into the foreseeable future.