Statement A collection of logically related building blocks of the same specialization (service, ABB or SBB). Description A catalog is a collection or register of building blocks of the same type. It is often aimed at a specific field of work, such as infrastructure, geo, integration. A catalog often contains building blocks of the same specialization, i.e. services, architecture or solution building blocks. However, the building blocks within this will often also be composed. A catalog can be seen as a showcase of generic and reusable architectural products. When these building blocks are used by a project, a number of architectural requirements, principles and requirements are met. The advantage for architecture is that these building blocks are reused. The advantage from a project perspective is that the architectural principles are met and that implementation is standardized and can probably be done faster. Due to changes in the environment (projects, LCM, innovations), the content of a catalog will regularly be adjusted, expanded or made more detailed elaborated. A catalog and the entities included in it thus become a "living" ecosystem. Initially, a supply-driven catalog model will be used. Becoming with others. Every domain architect creates a building block catalog for his domain. At a later stage this will be adapted to a demand-oriented elaboration, the so-called showcase model. architecture) concept can be included in a catalog.