10. API-First Design: A Survey of the State of Academia and Industry

The evolution of distributed and cloud-based systems has led the computing community to converge on Microservice Architecture (MSA) as a preferred solution to distributed software design. Established design methodologies applied to MSA (e.g., Data-, Model-, and Domain-Driven Design) assist in decision-making about business capacity and functionality encapsulated by the microservice. An expected result of microservice design is a well-defined Application Programming Interface (API) that facilitates the access of microservice and system capabilities. However, even with the extensive documentation and defined frameworks guiding practitioners in their execution of MSA, challenges exist in defining and exposing clean APIs. Further, the industry’s current focus on maximizing business capacities exposed by distributed systems emphasizes the importance of improving API design and implementation. To this end, API-First Design is emerging as a viable approach to MSA and API design. API-First principles suggest that all capabilities of an organization and its systems are exposed via an API and that the foundation of system design is the definition of clear and well-defined APIs. A significant challenge associated with API-First Design lies in the infancy of the topic and the necessity for peer-reviewed research defining guidelines for adoption and a baseline for future research. This paper seeks to move the state of the API-First Design methodology forward by exploring publications of the academic community and grey literature available on the topic. The paper concludes with a discussion about future research opportunities that may advance the understanding and adoption of API-First Design.