Patterns on Deriving APIs and their Endpoints from Domain Models

Domain-Driven Design (DDD) places the domain model at the center of all software development practices. Remote API design is crucial for developing distributed systems including, for example, microservice-based systems. While software practitioners realize APIs based on DDD models, clear guidance on how to derive APIs and API endpoints from domain model elements is still missing. Based on prior in-depth studies of practitioner sources on this and related topics, we have mined patterns to address these design problems. In particular, we present the domain model facade as api pattern which describes how to derive an API from a Domain Model. To explain further how derive API endpoints constituting the API from Domain Model elements, we present the aggregate roots as api endpoints, domain services as api endpoints, and domain processes as api endpoints patterns. In addition, we relate these patterns to the previously published patterns api description and api contract, both explaining how to describe APIs formally.The work of Cesare Pautasso and Uwe Zdun was supported by the API-ACE project, funded by SNF project 184692 and FWF (Austrian Science Fund) project I 4268. The work of Olaf Zimmermann is partially funded by the Hasler Foundation (DD-DSE, QDAR)