Cedar is an open source language and software development kit (SDK) for writing and enforcing authorization policies for your applications. You can use Cedar to control access to resources such as photos in a photo-sharing app, compute nodes in a micro-services cluster, or components in a workflow automation system. You specify fine-grained permissions as Cedar policies, and your application authorizes access requests by calling the Cedar SDK’s authorization engine. Cedar has a simple and expressive syntax that supports common authorization paradigms, including both role-based access control (RBAC) and attribute-based access control (ABAC). Because Cedar policies are separate from application code, they can be independently authored, analyzed, and audited, and even shared among multiple applications.