1. A system, comprising: a service gateway in communication with a first entity and a second entity, the service gateway comprising: a first interface module to receive, from the first entity, a message requesting performance of a service in an extensible set of services offered by the second entity, the message including a service name that corresponds to the service and an argument that includes data used to perform the service; an access control module to: make a first determination of whether the first entity is permitted to request performance of the service corresponding to the service name, make a second determination of whether the argument is permitted to be provided by the first entity, and make a third determination of whether the argument is permitted to be requested for the service corresponding to the service name; and a second interface module to selectively request performance of the service by the second entity based, at least in part, on results of the first, second, and third determinations of the access control module.