ReBAC vs RBAC: What's the difference and which should you choose?

Role-Based Access Control (RBAC) and Relationship-Based Access Control (ReBAC) are two common approaches for access control in applications. RBAC associates permissions with roles, which are then assigned to users, while ReBAC allows modeling complex relationships between entities such as users, resources, teams, etc. RBAC is simpler but rigid and struggles with dynamic or overlapping responsibilities. It's suitable when organizations have well-defined, stable roles, access patterns are primarily based on job functions, and performance is a critical concern. ReBAC provides more flexibility by determining access based on relationships between entities in the system. It mirrors how permissions work in real-world organizations where access often depends on dynamic connections rather than just job titles. ReBAC is suitable when access depends on dynamic relationships, you need contextual access decisions, your system models social or organizational graphs, and flexibility is more important than simplicity. Many systems successfully combine RBAC's simplicity for basic access control with ReBAC's flexibility for more complex scenarios. The choice between them should be based on specific needs, organizational structure, and growth plans of the organization.