A client device provides to a user, in an application associated with a social-networking service provided by a server system, a link to a page associated with a third-party service provider. The third-party service provider is distinct from the social-networking service. In response to user selection of the link, the page is loaded within the application. The page includes script for calling one or more application programming interfaces (APIs) of the server system. The client device calls the one or more APIs to obtain information associated with the user from the server system. The client device displays the page within the application, and uses the information associated with the user to conduct a transaction with the third-party service provider through the page.