API Designers in the Field: Design Practices and Challenges for Creating Usable APIs

Application Programming Interfaces (APIs) are a rapidly growing industry and the usability of the APIs is crucial to programmer productivity. Although prior research has shown that APIs commonly suffer from significant usability problems, little attention has been given to studying how APIs are designed and created in the first place. We interviewed 24 professionals involved with API design from 7 major companies to identify their training and design processes. Interviewees had insights into many different aspects of designing for API usability and areas of significant struggle. For example, they learned to do API design on the job, and had little training for it in school. During the design phase they found it challenging to discern which potential use cases of the API users will value most. After an API is released, designers lack tools to gather aggregate feedback from this data even as developers openly discuss the API online.