Modern applications face increasingly complex authorization needs, demanding efficient solutions to answer the pivotal question of "Who can access what?" Traditional role-based access control (RBAC) systems struggle with scale and complexity, leading developers to seek alternatives like Fine-Grained Authorization (FGA) and Relationship-Based Access Control (ReBAC). These models allow for expressive and scalable authorization by directly modeling relationships between users, groups, and resources. However, they face performance bottlenecks due to network latency during authorization checks. FGA Cache addresses this by enabling local evaluation of authorization logic while maintaining centralized modeling in Descope, significantly improving performance with sub-millisecond response times and eliminating network-related delays. This solution is particularly beneficial for high-volume authorization workloads, complex multi-tenant SaaS products, and AI applications requiring rapid, reliable permission checks. By integrating FGA Cache, organizations can enhance their authorization systems' performance without re-architecting their applications, ensuring fast, consistent access control in even the most demanding environments.