The goal with AppScale is to enable research and experimentation into cloud computing and to facilitate a “write once, run anywhere” programming model for the cloud, i.e., to expedite portable application development and deployment across disparate cloud fabrics. In this chapter, the authors describe the current AppScale APIs and the ways in which users can deploy AppScale clouds and applications in public and private settings. In addition, they describe the internals of the system to give insight into how developers can investigate and extend AppScale as part of research and development on next-generation cloud software and services.