Enabling Seamless Interoperability of Digital Systems in Smart Cities Using API: A Systematic Literature Review

Smart cities are envisioned to achieve an urban space where systems are connected to provide value added services to citizens and stakeholders, improve quality of life, and enhance institutional effectiveness. In smart cities, digital systems are deployed that comprise a wide range of service providers who collaborate to provide digital services to citizens. Hence, there is a need for accessible data that can be used to develop innovative applications and services to improve citizens' quality of life. Unfortunately, achieving interoperability of digital systems is challenging due to isolated systems referred to as vertical silos, which cannot communicate with each other due to lack of standardization of interfaces. Thus, interoperability is seen as a barrier for the seamless transfer of data between systems deployed in smart cities. In order to facilitate interoperability of systems in smart cities, this article conducts a Systematic Literature Review (SLR) to investigate the role of Application Programming Interface (API) to enable seamless interoperability in smart cities. An SLR was employed to guide the selection of studies retrieved to adequately address the formulated research questions. Findings from this study present the importance of interoperability in smart urban environments and help in providing an overview and categorization of existing interoperability solutions to make cities smarter. The findings also identified prior interoperability approaches in smart cities. Findings present a case scenario that depicts how APIs support seamless interoperability among digital systems in a smart city environment. Lastly, the findings elaborate on available API management tools and further suggest that APIs can significantly contribute to improve interoperability between digital systems and decrease barriers in providing innovative digital services in smart cities.