The EIRA© API viewpoint models an introductory overview of the focal Architecture Building Blocks required when modelling an API Interface. The ABBs included in the API viewpoint represent all the required Building Block necessary to design an API Interface accessible thoruh a web interface. Narrative: A [Client request for service] is made trough [Internet] and it triggers the [Authentication Service] which serves the [Request Validation Service]that triggers the [HTTP(s) Load Balancer] whichin turn triggers all the [Endpoints] related. Each [Endpoint] serves the [Application Service] which triggers the [App Component] that, in turn, triggers the [Data Access Service]. The [Data Access Service] provides access to the [Data Space] which is composed by the [SQL Data Space], [Read - Replica], [NoSQL Data Space] and [Virtual Data Space]. In the moment in which the [Endpoint] is triggered data flows to the [API Response] which is composed by [Data] and [Represenation] accessed by a [Request Validation Service]. The [API Response] triggers the response that is provided to the user who requetd the data in the first instance.