The use of application programming interfaces (APIs) to develop and design technological forms of structured exchanges is an increasingly prevalent practice at present, allowing data to be shared, automated, circulated and redistributed in wider computational culture. Despite acting as key infrastructural elements and connectors, the prominence and importance of APIs is still under recognised. Via a brief survey of the history of API development and then closer regulatory and technical analysis of the long standing, non-profit net.art generator (nag) (1997), this study aims to bring to the fore key sociotechnical elements of API design. Particular attention is given to protocological forms of control as these can be enacted through APIs via the regulations, terms of service and specific operational processes and affordances of fetching networked data. net.art generator uses the Google API and URL and specific attention is given to Google’s setting of terms for exchange. In doing so, we give a few suggestions for how anyone working with APIs might think through certain key questions around the creation and use of APIs, particularly in regards to the parameters of openness, accessibility and terms of inclusivity that APIs set upon practices of knowing, sharing, participation and exchange.