Being able to specify and verify contractual application properties at the architecture level allows architects to build better architected and more reliable systems. In this paper, we propose a model-based framework for designing contractualized architecture, independently of any paradigm (components or services). It enables a software architect to express the structural, behavioral, dataflow and QoS properties of his/her application. Our framework composes these properties in order to compute and check the properties of the assemblies incrementally. This allows architects to see the influence of their design decisions on the quality of his/her architecture and thus helps them to better design their systems architecture.