Service modeling is an important step in designing service-oriented systems. There are multiple levels of design because service sci-ence includes both the business rationale and the IT implementation ofthe services. As business and IT perspectives differ, the modeling tech-niques are different, and often the respective modeling languages aredisconnected or ad-hoc. We propose a new service-modeling approachfor connecting the business modeling and the web service modeling bypresenting these two perspectives in a single model. We present a multi-stage modeling process for capturing different perspectives and creatingmodels iteratively by working with levels of abstraction from higher tolower. The model is then used as an input in order to generate a RESTAPI specification in the OpenAPI format to feed the next stages of theservice life-cycle.