In this paper we present MetaFrame, an environment for formal methods-based, application-specific software design. Characteristic for MetaFrame are the following features: library-based development, meaning software construction by combination of components on a coarse granular level, incremental formalization, through successive enrichment of a special-purpose development environment, and library-based consistency checking, allowing continuous verification of application- and purpose-specific properties by means of model checking.
These features and their impact for application developers and end users will be illustrated along an industrial application, the design of intelligent network (IN) services.