From their site: Workday Web Services (WWS) provide developers with access to Workday’s robust business services via standards-based web services. These web services provide operations for interaction with many critical areas of Workday, including benefits, organization, payroll, and recruiting. Currently, you must be a Workday customer or Certified Integration Partner in order to use WWS.
Successful enterprises rely on the latest technology to drive business operations, intelligence, and efficiency. APIs are the driving force of business application development. In this article, we highlight twelve top business APIs, chosen by popularity from the visitors of ProgrammableWeb.