1. A method comprising: receiving, at one or more computer systems, a document that references one or more user interface components, wherein the document is in a native application format associated with a native application, wherein the native application includes or is in communication with an application server via an integration module of the native application, and wherein at least some of the user interface components correspond to one or more attributes of a data model of a web-based application that is in communication with the application server; receiving, at the one or more computer systems, a value of a property defined by a user on an attribute of the data model, the value comprising an expression; receiving, at the one or more computer systems, data representing the one or more attributes of the data model from the application server responsive to processing the one or more user interface components; and rendering, with one or more processors associated with the one or more computer systems, the document using the expression and the data, wherein the rendering the document comprises rendering the at least some of the user interface components by incorporating the data into the at least some of the user interface components based at least on evaluating the expression, and wherein the document is configured to act as a user interface for the web-based application by extending functionality provided by the web-based application to the native application, and the user interface comprises the at least some of the user interface components.