State of the Practice in Application Programming Interfaces (APIs): A Case Study

Application Programming Interfaces (APIs) have become prevalent in today’s software systems and services. APIs are basically a technical means to realize the co-operation between software systems or services. While there are several guidelines for API development, the actually applied practices and challenges are less clear. To better understand the state of the practice of API development and management in the industry, we conducted a descriptive case study in four Finnish software companies: two consultancy companies developing software for their customers, and two companies developing their software products. As a result, we identified five different usage scenarios for APIs and emphasize that diversity of usage should be taken into account more explicitly especially in research. API development and technical management are well supported by the existing tools and technologies especially available from the cloud technology. This leaves as the main challenge the selection of the right technology from the existing technology stack. Documentation and usability are practical issues to be considered and often less rigorously addressed. However, understanding what kind of API management model to apply for the business context appears as the major challenge. We also suggest considering APIs more clearly a separate concern in the product management with specific practices, such as API roadmapping.