To ease the design of the API Spec, an existing meta model for the definition of the business domains was wanted. The choice of the spec team fell on BIAN (https://www.bian.org/) as conceptual foundation of the Common API Specification for Banking (CAPS).
The Banking Industry Architecture Network e.V. (BIAN) is an independent, member owned, notfor-profit association to establish and promote a common architectural framework for enabling banking interoperability. It was established in 2008. The BIAN meta model has three elements that capture the design of the BIAN Service Landscape.
This is the highest-level classification. A business area groups together a broad set of business capabilities. For the BIAN Service Landscape they are defined to be aspects of business activity that have similar supporting application and information-specific needs.
At the next level, business domains define a coherent collection of capabilities within the broader business area. In the BIAN Service Landscape the business domains are associated with skills and knowledge recognizable in the banking business.
This is the finest level of partitioning, each defining unique and discrete business capabilities. The Service Domains are the ‘elemental building blocks’ of a service landscape. The Service Domain relates to generic capabilities that do not vary in their scope, but the definitions of the Business Domain and Business Area are classifications that are specific to a particular Service Landscape layout. The Service Landscape layout can be varied depending on use.