A specification of one or more query response modules from a third-party entity different from an entity providing a search service is received. A search query from a user is received. The search query is processed at least in part with the search service to determine whether any of the one or more query response modules are applicable to the search query. In response to a determination that at least one of the one or more query response modules is applicable to the search query, one of the query response modules is selected for the search query. The selected query response module is executed to determine a module answer content. The search query is processed to identify links to content responsive to the search query. A response to the search query is provided including by embedding the module answer content in a user interface providing at least a portion of the identified links.