Techniques are described for configuring content page(s) based on context information. A request for page(s) may be analyzed to determine context information, such as the requesting device type, application type, and so forth. The context information may be employed to evaluate conditional statement(s) to determine a configuration of feature(s) of the page(s), the conditional statement(s) included in configuration file(s). In some cases, a configuration file may be associated with the particular user interface (UI) to be presented, such as an online marketplace. Information in a configuration file for a particular UI may override information in a generic configuration file that is applicable to configure multiple UIs. Techniques are also described for using test module(s) to validate the operation of a UI in response to an action, instead of making call(s) to external service(s) in response to an action.