Authorization In Practice

Authorization determines what an authenticated entity, such as a user or an AI agent, is permitted to do, as distinct from authentication which verifies who they are. Authorization can be implemented at multiple layers, including on the client for user experience, in middleware for broad protection, or at specific API endpoints. The most effective place to enforce authorization is at the boundary of the backend, where user intent is clearest within a trusted environment. For comprehensive security, a "defense in depth" strategy is recommended, layering controls through software abstractions and service boundaries to create overlapping protections.