The authentication glue you need.

Apache Casbin: an authorization library that supports access control models like ACL, RBAC, ABAC.

✨ 开源、免费、一站式 Java 权限认证框架，让鉴权变得简单、优雅！—— 登录认证、权限认证、分布式 Session 会话、微服务网关鉴权、SSO 单点登录、OAuth2.0 统一认证、jwt 集成、API Key 秘钥授权、API 参数签名

Internet-scale OpenID Certified™ OpenID Connect and OAuth2.1 provider that integrates with your user management through headless APIs. Solve OIDC/OAuth2 user cases over night. Consume as a service on Ory Network or self-host. Trusted by OpenAI and many others for scale and security. Written in Go.

ZITADEL - Identity infrastructure, simplified for you.

🧑‍🚀 Authentication and authorization infrastructure for SaaS and AI apps, built on OIDC and OAuth 2.1 with multi-tenancy, SSO, and RBAC.

Open Policy Agent (OPA) is an open source, general-purpose policy engine.

Expose your FastAPI endpoints as Model Context Protocol (MCP) tools, with Auth!

Apereo CAS - Identity & Single Sign On for all earthlings and beyond.

CASL is an isomorphic authorization JavaScript library which restricts what resources a given user is allowed to access

Open Source, Google Zanzibar-inspired database for scalably storing and querying fine-grained authorization data

The user infrastructure platform. You choose the frontend, backend, and database. Hexclave handles everything else.

An open-source authorization as a service inspired by Google Zanzibar, designed to build and manage fine-grained and scalable authorization systems for any application. — Permify is now part of FusionAuth 🎉

The authorization Gem for Ruby on Rails.

A high performance and flexible authorization/permission engine built for developers and inspired by Google Zanzibar

Doorkeeper is an OAuth 2 provider for Ruby on Rails / Grape.

Policy and data administration, distribution, and real-time updates on top of Policy Agents (OPA, Cedar, ...)

The Developer Platform for Modern APIs

The most scalable and customizable permission server on the market. Fix your slow or broken permission system with Google's proven "Zanzibar" approach. Supports ACL, RBAC, and more. Written in Go, cloud native, headless, API-first. Available as a service on Ory Network and for self-hosters.

Orchestrate end-to-end encryption, cryptographic identities, mutual authentication, and authorization policies between distributed applications – at massive scale.