> ## Documentation Index
> Fetch the complete documentation index at: https://openfga.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Learn Authorization

> Authorization concepts explained — Zanzibar, ReBAC, RBAC, ABAC, fine-grained authorization, and policy engines — with FGA examples.

A short reference for the concepts behind OpenFGA. Each page is a focused explainer with an OpenFGA example so you can map the theory to the model language.

* **[Google Zanzibar](/docs/learn/zanzibar)** — the paper that started the ReBAC wave.
* **[ReBAC: Relationship-Based Access Control](/docs/learn/rebac)** — what it is, when to use it.
* **[RBAC vs. ReBAC](/docs/learn/rbac-vs-rebac)** — when roles run out.
* **[ABAC vs. ReBAC](/docs/learn/abac-vs-rebac)** — attributes versus relationships.
* **[Fine-Grained Authorization](/docs/learn/fine-grained-authorization)** — what "fine-grained" actually buys you.
* **[Policy Engines vs. Relationship Engines](/docs/learn/policy-engine)** — Rego, Cedar, OPL, and where OpenFGA fits.