API design up until now has been guided by the assumption that the server is authoritative and the client is subservient. “Leaf computing” challenges this assumption with a new paradigm for designing APIs, where clients are authoritative and autonomous, but no less connected. This application architecture gives users control over their data and limits the operational costs and security liabilities of the provider. This talk walks through several common API integration patterns and reimagines them for a less cloud-y future.