Open Policy Agent is a general-purpose policy system designed to policy-enable other projects and services. The OPA Frameworks repository defines opinionated APIs for policy that are less flexible than the OPA API but are well-suited to particular classes of use cases. For example, Role Based Acces Control (RBAC), Attribute Based Access Control, Access Control Lists (ACLs), and IAM can all be implemented on top of the OPA API and its policy language, and could each be defined as an OPA Framework. One analogy from the web development world that seems to help people is that Frameworks are to OPA as Rails is to Ruby.