1. A computer program product comprising a non-transitory machine-readable medium storing instructions that, when executed by at least one processor, cause the at least one processor to perform operations comprising: retrieving by a server, a list of underlying business object nodes required for presentation of an organization-specific user interface corresponding to an organization from which a call for an instance of the organization-specific user interface is received at the server; creating a portal business object that matches a structure of the organization-specific user interface and that includes one portal business object node corresponding to each user interface element of a plurality of user interface elements of a structure of the organization-specific user interface, each user interface element of the plurality of user interface elements having a dependency upon at least one of the underlying business object nodes, the creating of the portal business object comprising dynamically defining the portal business object during runtime based on a user interface model definition established prior to runtime, the user interface model creating the organization-specific user interface; modifying the organization-specific user interface, the modifying comprising one or more of adding a new element to the organization-specific user interface and modifying an existing element of the organization-specific user interface, the adding of the new element or the modifying of the existing element requiring a new dependency upon an additional underlying business object node that is not on the list; creating a new portal business object node in the portal business object; establishing the new dependency between the new element or existing element and the new portal business object node; and providing access to the portal business object for the user interface model by calling the underlying business object nodes according to the portal business object.