Role-Based Access Control (RBAC) is a critical framework for managing user permissions, and Keycloak, an open-source Identity and Access Management tool, facilitates user authentication with support for protocols like OpenID Connect and SAML 2.0, making it ideal for Identity Federation and Single Sign-On. However, Keycloak's built-in RBAC features are limited in dynamic management and scaling for complex applications. To address these limitations, integrating Keycloak with Permit.io enhances its capabilities by introducing fine-grained permissions and dynamic policies, supporting models like Attribute-Based Access Control (ABAC) and Relationship-Based Access Control (ReBAC). This integration allows for scalable multi-tenancy management and efficient policy management using both policy-as-code and no-code tools. The guide provides a comprehensive walkthrough of setting up Keycloak for authentication, configuring a NestJS application, and using Permit.io for advanced authorization, demonstrating how to synchronize users and roles between Keycloak and Permit for seamless access control in complex, multi-tenant environments.