In recent years, many firms have launched public Application Programing Interfaces (APIs). Through APIs, digital business strategies are enacted. Firms, however, struggle with how to successfully design APIs. In this report, we address this issue by identifying API strategy archetypes and describe typical scenarios for their application. Based on desk research, we identify ten elements that determine business-oriented API design. We report the results of a cluster analysis of 96 randomly sampled and coded APIs. We identify three archetypes of API-enabled service innovation that are characterized by distinct configurations of API elements: Integrator, Free Data Provider and Mediator.