A method and apparatus to employ a service proxy to personalize service messages by automatically supplying the interface parameters used for communications between a Service provider and its client businesses. The service proxy does this according to context parameters that the client businesses specify during configuration of the messages used to communicate with one or more services. For simpler administration, the context variables may be organized in multiple kinds of hierarchies by which communications parameters specified at a higher level are automatically applied to categories at a lower level, although parameters specified directly for a lower-level category will override parameters from a higher category.