In a web application platform context, web service proxy interface augmentation is provided without undue loss of customization capabilities. After obtaining an address of a web service endpoint, sending a metadata query to the endpoint, and extracting operational information from the response, a contract is generated in the form of an interface. The interface does not rely on non-contract programming constructs. A file containing the interface is added to a project in an integrated development environment (IDE). From a developer perspective, the IDE displays service application(s) of a server farm identified by the developer. The developer selects a service application and receives a list of web service endpoint(s). After choosing an endpoint, the developer receives an automatically generated interface containing operational information for an operation exposed by the web service endpoint. The developer also creates in the IDE a web proxy project item that includes the interface.