Honeysuckle [1] is a new programming language that allows systems to be constructed from processes which communicate under service (client-server or master-servant) protocol [2]. The model for abstraction includes a formal definition of both service and service-network (system or component) [3]. Any interface between two components thus forms a binding contract which will be statically verified by the compiler. An account is given of how such an interface is constructed and expressed in Honeysuckle, including how it may encapsulate state, and how access may be shared and distributed. Implementation is also briefly discussed.