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

OpenID Connect (OIDC) identity and OAuth 2.0 provider with pluggable connectors

一账通是一款开源的统一身份认证授权管理解决方案，支持多种标准协议(LDAP, OAuth2, SAML, OpenID)，细粒度权限控制，完整的WEB管理功能，钉钉、企业微信集成等，QQ group: 167885406

Node.js library for SAML SSO

Login.gov Core App: Identity Provider (IdP)

Simple SAML Identity Provider (IdP) for Node

This is a MongoDB provider for the ASP.NET Core 2 Identity framework

[UNMAINTAINED] Serverless Authentication as a Service (AaaS) provider built on top of AWS Cognito

Apache Syncope

Ruby SAML Identity Provider, best used with Rails (though not required)

A centralized login and SSO application to authenticate several websites and mobile apps.

Lightweight SAML Identity Provider

Building blocks for servers implementing Simple Cloud Identity Management v2

Spring Boot OAuth 2.0 & OpenID Connect Identity Provider / Authorization Server

A ranked list of awesome Digital Identity open source projects

Mountable Rails engine that provides OpenID server/identity provider functionality

Get up and running quickly with Okta's OAuth as a Service and your favorite API Gateway.

Projeto Login Cidadão

ASP.NET Core Identity Provider for NHibernate

A turnkey OAuth & authentication system, designed for both Cloudflare Workers and Node.js