The service contract is one of the fundamental design principles in the Service Oriented Architecture (SOA). Its goal is to express the features (e.g., services and capabilities) of Service Providers (SPs) so Service Consumers (SCs) can identify them to communicate correctly. The two most known service contracts in the literature are: WSDL for SOAP and WADL for REST. We identify that these service contracts suffer from several problems (e.g., they only allow expressing a limited set of features). Also, we notice from the literature a lack of service contracts dedicated for SC. In order to overcome these problems, we propose two Features Models (FMs) based on SOA design patterns that can be considered as generic and formal service contracts for SP and SC. We propose extensions to the Feature MetaModel (FMM) and semantic constraints that ensure generating fully functional, valid, customized and consistent SPs and SCs from the proposed FMs.