Auth0 Fine-Grained Authorization # FGA that’s ready for the AI age Better secure your apps, RAG systems, MCP servers, and AI agents with Auth0 Fine-Grained Authorization (FGA) built on an enterprise-grade identity platform. - [Get started](https://auth0.com/signup?signUpData=%7B%22category%22%3A%22button%22%7D) - [Contact us](https://auth0.com/contact-us?place=hero&type=button&text=talk%20to%20sales) ## Authorization that scales with your complexity ### The problem In-house, custom auth logic can’t scale with the rapidly-evolving AI landscape, especially when securing multi-tenant B2B APIs for autonomous agents and MCP clients. These complex authorization needs create massive attack surfaces. ### The solution Auth0 FGA provides a unified, relationship-based [platform](https://auth0.com/platform) that helps secure multi-tenant B2B APIs and apps, and decouples complex authorization logic from your code. It enforces strict data isolation and least-privilege access for humans, agents, and MCP clients across billions of resources with enterprise-grade reliability. [Get Started with Auth0 FGA](https://docs.fga.dev/getting-started) **Better secure the AI future** More secure APIs are essential before exposing them to autonomous AI systems and agents. Auth0 FGA helps enforce least-privilege access, helping ensure agents access only data authorized to them, and mitigating risks like prompt injection and data leakage. [Explore Auth0 for AI Agents](https://auth0.com/ai) **Speed up innovation and time to market** Stop writing tedious, custom authorization logic for collaborative features like sharing and multi-level roles. Auth0 FGA replaces this with delegation and on-behalf-of flows, allowing you to safely expose secure APIs to third-party applications like AI agents. [Read the blog](https://www.okta.com/blog/product-innovation/solving-authorization-for-b2b-saas-at-okta/) **Scale seamlessly** Auth0 FGA provides a Tier-Zero Reliability (99.99% availability SLA*) and low latency. It enables a true Zero Trust architecture by enforcing context-aware access for every request to millions of users and billions of resources. Auth0 FGA centralizes all permission checks, providing a single, immutable audit trail required for compliance with regulations like GDPR and HIPAA. *Based on 12-month availability, as indicated on [trust.okta.com](https://trust.okta.com). [Read the blog](https://auth0.com/blog/auth0-fga-logging-api-a-complete-audit-trail-for-authorization/) ## Built for AI and the latest use cases **Better secure APIs for enterprise AI and RAG** Help ensure your AI agents access only authorized documents and information. Mitigate prompt injection and non-deterministic agent actions that unsecured APIs cannot prevent, while controlling agent-resource interaction at the MCP layer to better secure your APIs for advanced AI patterns. [Learn more ↗](https://auth0.com/ai/docs/get-started/authorization-for-rag) **Enable API authorization for any resource or identity** Manage all access (users and agent identities) to any resource type using fine-grained, dynamic policies. Implement advanced policies for delegation, time limits, transaction controls, and entitlements, providing the flexibility and expressiveness modern authorization demands. [Learn more ↗](https://docs.fga.dev/) **Help support compliance** Keep a log of who changed permissions and when, as well as who accessed specific resources, providing a single, immutable audit trail required to prove to auditors the actions taken by users and AI agents (GDPR, HIPAA). [Learn more ↗](https://www.youtube.com/watch?v=6jM8OL_K9vw) ### Seamlessly scalable Manage complex authorization scenarios efficiently, and with low latency, as your user base and systems grow. Easily manage permissions to millions of users and billions of resources. FGA is available for multi-region deployment with a 99.99% SLA. ### Flexible and centralized Continuously iterate and evolve your applications by moving your authorization to a centralized place, allowing the flexibility to release new products faster. ### Granular access Improve security by defining group and user permissions for every application resource (like documents, records, projects, accounts, or any other resource). ### Frictionless collaboration Allow your users and partners to collaborate more securely. Easily manage groups, teams, organizations or any set of users and enable content sharing with just a single API call. ## Features built for developers Empower your development teams to programmatically define authorization logic and integrate with your existing systems. [Read the docs →](https://docs.fga.dev) ## Auth0 FGA leverages the identity platform you already trust > “There has been a 1,025% increase in AI-related vulnerabilities (CVEs) in a single year—and 77.4% of those are directly tied to API security issues.” > — Forrester, The State Of Application Security, 2025 > [Read more](https://www.forrester.com/report/the-state-of-application-security-2025/RES182779) ## Trusted by developers > “Auth0 FGA has fundamentally transformed our ability to manage workspaces. Before, relationship-based access control across multiple workspaces was simply not feasible. With Auth0 FGA, we can instantly set up new workspaces with complex, fine-grained authorization structures. This leap in functionality allows us to meet our enterprise clients’ granular access control needs in ways we couldn't have imagined before.” > — Bryce Easley, Senior Director of Engineering > “Auth0 FGA allows us to offload the complexity of building and maintaining a permissions system so our teams can focus on what matters most: delivering features for our customers. It unified sharing across our product suite and established a foundation that lets teams ship collaboration features faster without reinventing access control.” > — Jason Poole, Director of Engineering **Whitepaper** ## Your technical primer for Fine-Grained Authorization Context, concepts, and how to get started with implementing the access control today’s SaaS apps require. [Go to download](https://auth0.com/resources/whitepapers/fine-grained-authorization-technical-primer) ## Built on OpenFGA - [Whitepaper: Fine-Grained Authorization (FGA): A technical primer](https://auth0.com/resources/whitepapers/fine-grained-authorization-technical-primer) - [Blog: How Fine-Grained Authorization Solves Broken Object Access Level Authorization](https://auth0.com/blog/how-fine-grained-authorization-solves-critical-api-security-risk/) - [Blog: Auth0 FGA Logging API: A Complete Audit Trail for Authorization](https://auth0.com/blog/auth0-fga-logging-api-a-complete-audit-trail-for-authorization/) ## FAQ ### What is Auth0 Fine-Grained Authorization (FGA)? Auth0 Fine-Grained Authorization (FGA) is a relationship-based access control (ReBAC) service that allows developers to model complex permissions at scale. Inspired by Google's Zanzibar, FGA decouples authorization logic from application code, enabling precise, real-time access decisions for millions of users and billions of resources across B2B SaaS and AI-driven platforms. ### How does Auth0 FGA secure AI agents? Auth0 FGA helps secure AI agents by enforcing least-privilege access at the resource level. By modeling the relationships among users, agents, and data, FGA helps ensure that an AI agent can access only the specific documents or tools authorized for that session, mitigating risks such as prompt injection and unauthorized data leakage in RAG pipelines. ### Is Auth0 FGA based on OpenFGA? Yes, [Auth0 FGA](https://docs.fga.dev/) is built on [OpenFGA](https://openfga.dev/), an open-source project within the [Cloud Native Computing Foundation (CNCF)](https://www.cncf.io/). By building on an open standard, Auth0 verifies that developers aren't locked into a proprietary system and can leverage a community-driven authorization model that is both highly flexible and battle-tested for enterprise-grade reliability. ### Can I use FGA for B2B multi-tenancy? Absolutely. Auth0 FGA is ideal for B2B SaaS applications that require complex, multi-level roles and resource sharing between organizations. It allows you to model intricate hierarchies—such as 'Manager of Department' or 'Editor of Document'—and centralize all permission checks in a high-performance service that scales with your most demanding enterprise clients. ### What are the performance limits of Auth0 FGA? Auth0 FGA is designed for 'Tier-Zero' reliability and low-latency response times, even at massive scale. It can handle billions of authorization tuples and millions of requests per second, helping ensure that permission checks don't become a bottleneck for your application's performance, regardless of how complex your authorization model becomes.