A method for dynamically constructing a web page is disclosed which includes receiving a uniform resource locator identifying a web page. The web page references a plurality of elements. The method also includes receiving a user identifier representing a user and evaluating each of the referenced elements based on the user identifier to identify a subset of at least one element the user is authorized to access. The method further includes determining a data conversion specification associated with the user and determining a data representation specification associated with the user. The subset of elements that the user is authorized to access is converted and presented to the user. Systems and computer-readable storage media for defining and presenting a composite web page are also disclosed.