1. A method for configuring an application on a computer system, comprising: receiving a request to configure the application from a client associated with the application, wherein the computer system is external to the client, and wherein the request comprises an application context describing a state of the application at runtime; obtaining a rule comprising a conditional expression for configuring the application at runtime; parsing the rule to extract a symbol and an operator; converting the conditional expression into a tree comprising the symbol and the operator; replacing the symbol with a value from the application context using a domain map to find a context data source publishing the value; calculating a correct configuration for the application based on the application context by evaluating the tree after replacing the symbol; obtaining an application object associated with a plurality of options for configuring the application; selecting an option of the plurality of options based on the correct configuration for the application; and sending, from the computer system and in response to the request, an instance of the application object encapsulating the option to the client, wherein the application object is used to set a configuration of the application to the correct configuration.