Auth0

OpenID Connect and OAuth 2.0 service that is available on the cloud as a SaaS.

Authelia

Open Source authentication, authorization server and portal fulfilling the identity and access management (IAM) role of information security in providing single sign-on (SSO).

Authentik

Open Source Identity Provider focused on flexibility and versatility.

Authlete

Set of APIs for developers to implement OAuth authorization servers and OpenID Connect identity providers.

AWS Cognito

Cognito by Amazon Web Services has OpenID Connect provider in addition to IAM capabilities.

Clerk

Authentication with user management and OpenID Connect provider capabilities.

Cloudentity

Cloud Identity and Authorization Platform with FAPI and eKYC support.

Connect2id

OpenID Connect SSO and IdP server for enterprise.

Curity Identity Server

API Security solution that brings identity and API access management together.

Descope

OpenID Connect Provider and Identity Federation solution that provides drag and drop user authentication and authorization flows.

Dex

Provider that acts as a portal to other identity providers through "connectors." like LDAP, SAML, OIDC or established identity providers like GitHub, Google, and Active Directory.

Duende IdentityServer

ASP.NET Core OpenID Connect Provider solution.

Duo

OpenID Connect Provider and IdP solution developed by Cisco.

FrontEgg

A Customer Identity solution for SaaS platform with OpenID Connect Provider capability.

Keycloak

Open Source project powered by RedHat which provides user federation, strong authentication, user management, fine-grained authorization, and more.

Gluu

OpenID Connect Provider and FAPI certified solution and integrated with IAM.

Gravitee.io

Open Source OpenID Connect/OAuth 2.0 provider aims to be a bridge between applications and identity providers to authenticate, authorize and getting information about user accounts.

Kinde

OpenID Connect and OAuth 2.0 service that is available on the cloud as a SaaS.

LoginRadius

A SaaS CIAM that can act as an OpenID Connect provider.

Logto

An Open-source solution designed for Customer Identity and Access Management (CIAM) and Workforce Identity Management with OpenID Connect based authentication.

Okta

Extensible solution that enables both customer and workforce identity with federation, single sign-on, API security and workflows for both cloud and on-prem solutions.

Microsoft Entra ID

Software component developed by Microsoft providing single sign-on access to systems and applications.

MITREid Connect

Open Source OpenID Connect reference implementation in Java.

OpenIddict

.NET Open Source OpenID Connect Provider implementation with ASP.NET Core 2.1 (and higher) applications support.

OneLogin

SaaS Employee and Customer IAM solution with OpenID Connect Provider capabilities.

Ory Hydra

Open Source OpenID Certified™ OpenID Connect and OAuth Provider.

Ory Polis (formerly BoxyHQ Jackson)

Open Source Enterprise SSO bridges or proxies a SAML login flow to OpenID Connect with also user directory sync capabilities.

panva/node-oidc-provider

Open Source and certified OpenID Connect provider implementation in Node.js with FAPI 1.0 and FAPI 2.0 support.

PingFederate

Federation server that provides secure single sign-on, API security and provisioning for enterprise customers, partners, and employees.

Pocket ID

A simple OpenID Connect Provider that allows users to authenticate with their passkeys.

SiteMinder

An IAM provided by Broadcom with OpenID Connect Provider support.

SSOJet

A OpenID Connect based solution that seamlessly integrates enterprise SSO into your B2B SaaS.

Scalekit

OpenID Connect provider for B2B applications, acting as the application's OpenID Provider (OP) for hosted enterprise SSO.

Transmit Security

A CIAM solution that supports an OpenID Connect-based integration.

WSO2 Identity Server

Identity Server which provides modern identity and access management capabilities that can be easily built into organization's customer experience (CX) applications.

Zitadel

Open Source Identity solution with OpenID Connect provider (OP) and SAMLv2 ready to use.

Alibaba Cloud IDaaS

Alibaba Cloud OpenID Connect Provider as a service.

SecureAuth

Identity security platform that provides OpenID Connect Provider capabilities.

FusionAuth

Open Source Identity and Access Management (IAM) solution with OpenID Connect Provider capabilities.

IBM Verify

OpenID Connect Provider and Identity as a Service (IDaaS) solution by IBM.

MojoAuth

An OpenID Connect-based passwordless authentication platform using passkeys, magic links, and OTPs.

CyberArk Identity

Identity security solution that provides OpenID Connect Provider capabilities.

SailPoint

Enterprise identity security platform that provides OpenID Connect Provider capabilities.

SAP Customer Identity

SAP's OpenID Connect Provider and Identity as a Service (IDaaS) solution.

WorkOS

An identity management platform that enables organizations to provide secure access to their workforce, customers, and partners.

OpenID Foundation conformance suite

Test conformance suite to obtains OpenID Foundation certification which covers OpenID Connect, FAPI1-Advanced, FAPI2, FAPI-CIBA and OpenID for Identity Assurance (ekyc).

liboauth2

Generic library to build C-based OpenID Connect Provider and Relying Party.

mod_auth_openidc

OpenID Connect Relying Party certified implementation for Apache Server 2.x.

ngx_oauth2_module

OpenID Connect Relying Party certified implementation for Nginx.

IdentityModel.OidcClient

C# / .NET OpenID Connect relying party client certified library for native mobile/desktop applications.

openid_client

OpenID Connect Relying Party client library for Dart in Flutter, Web and Command Line.

oidcc

Certified OpenID Connect Relying Party client library for Erlang and Elixir with FAPI support.

coreos/go-oidc

Go OpenID Connect client developed by CoreOS.

golang.org/x/oauth2

Official Golang client implementation for OAuth 2.0 spec with OpenID Connect support.

zitadel/oidc

OpenID Connect client and server library certified by the OpenID Foundation.

com.google.oauth-client/google-oauth-client

OAuth Relying Party Java library written by Google for OAuth 2.0 with Android support.

com.nimbusds/oauth2-oidc-sdk

Java SDK developed by connect2id with OpenID Connect, FAPI, Federation and eKYC / Identity Assurance extensions.

Spring Security

Java framework for securing Spring-based applications with OpenID Connect and OAuth 2.0 support.

openid-client

OpenID Certified™ Relying Party (OpenID Connect/OAuth 2.0 Client) implementation for Node.js.

oauth4webapi

OAuth 2/OpenID Connect library for JavaScript Runtimes.

oidc-client-ts

TypeScript OpenID Client and OAuth 2.0 client for browser-based applications.

Better Auth

TypeScript Framework agnostic authentication library for SPAs and server-side applications.

nuxt-auth for Nuxt 2

Zero-boilerplate authentication support for Nuxt.js 2.

nuxt-auth for Nuxt3

Nuxt 3 user authentication and sessions library. nuxt-auth wraps NextAuth.js.

angular-auth-oidc-client

Angular certified library with OAuth 2.0 and OpenID Connect flows, and Angular schematics.

angular-oauth2-oidc

Library which bring support for OAuth 2.0 and OpenID Connect (OIDC) in Angular.

ocaml-oidc

Certified OpenID Connect Relying Party implementation in OCaml.

Laravel Socialite

Laravel wrapper around OAuth 1 & OAuth 2 libraries with OpenID Connect support.

thephpleague/oauth2-client

Integration with OAuth 2.0 service providers for PHP.

Symfony Security

PHP Security component with OpenID Connect support.

Authlib

Python library in building OAuth and OpenID Connect servers and clients.

mozilla-django-oidc

A Django OpenID Connect relying party library maintained by Mozilla.

openid_connect

Ruby OpenID Connect Relying party (RP) and Provider (OP) library.

omniauth_openid_connect

OpenID Connect Strategy for Ruby OmniAuth library.

openidconnect

OpenID Connect Relying party (RP) library for Rust.

MiniOrange OAuth SSO

Wordpress OAuth and OpenID Connect plugin developed and actively maintained by MiniOrange.

oauth2-proxy

Reverse proxy adding OpenID Connect and OAuth 2.0 based authentication in front of any application.

lua-resty-openidc

OpenID Connect Relying Party and OAuth 2.0 client Lua library for NGINX/OpenResty.

Kong OpenID Connect

OpenID Connect Relying Party plugin for the Kong API Gateway.

Apache APISIX openid-connect

OpenID Connect Relying Party plugin for the Apache APISIX API Gateway.

traefikoidc

OpenID Connect Relying Party middleware plugin for Traefik.

caddy-security

OpenID Connect Relying Party authentication plugin for the Caddy web server.

Vouch Proxy

SSO solution using OpenID Connect for Nginx and Traefik reverse proxies.

authorization_code

OAuth 2.0 Authorization Code Grant Type which fit well public client authorization like web apps.

refresh_token

OAuth 2.0 Refresh Token Grant Type used to exchange a refresh token against a short life access token and sometime a new refresh token as well.

client_credentials

OAuth 2.0 Client Credentials Grant providing a way to get token without user interaction which fit well machine to machine communications.

implicit

OAuth 2.0 Implicit Grant Type which is deprecated and should not be used anymore.

password

OAuth 2.0 Resource Owner Password Credentials Grant Type which is not recommended to use anymore.

urn:ietf:params:oauth:grant-type:device_code

OAuth 2.0 Device Authorization Grant focused on interaction with user outside of a browser context like smart TVs.

urn:ietf:params:oauth:grant-type:jwt-bearer

JSON Web Token (JWT) Profile for OAuth 2.0 used to authorize a client to get an access token with another JWT issued by a trusted provider.

urn:ietf:params:oauth:grant-type:saml2-bearer

Security Assertion Markup Language (SAML) 2.0 Profile for OAuth 2.0 used to authorize a client to get an access token with a SAML assertion issued by a trusted provider.

urn:ietf:params:oauth:grant-type:token-exchange

OAuth 2.0 Token Exchange is a Grant Type which provides a way to get tokens from another token and give the ability to add an actor claim.

Proof Key for Code Exchange (PKCE) Extension

Extension of the Authorization Code flow adding security layer against code interception attack.

CBOR Web Token (CWT)

CBOR format used for tokens in the context of OpenID Connect and OAuth 2.0.

OpenID Connect Core 1.0

Defines the core OpenID Connect functionality: authentication built on top of OAuth 2.0 and the use of Claims to communicate information about the End-User. It also describes the security and privacy considerations for using OpenID Connect.

The OAuth 2.0 Authorization Framework

Underlying OAuth 2.0 protocol OpenID Connect is based on.

JSON Web Token (JWT)

JWT specifications used for different tokens mentioned in OAuth 2.0 and OpenID Connect specifications.

JSON Web Token (JWT) Profile for OAuth 2.0 Access Tokens

JWT format and validation specifications in the context of OAuth 2.0.

JSON Web Key (JWK)

JavaScript Object Notation (JSON) data structure that represents a cryptographic key provided by OpenID Connect Provider.

JSON Web Encryption (JWE)

Specifications for JWE which represents encrypted content using JSON-based data structures.

JSON Web Signature (JWS)

Specifications for JWS which represents content secured with digital signatures.

OAuth 2.0 Threat Model and Security Considerations

Known threats using OAuth 2.0 / OpenID Connect and countermeasures.

OAuth 2.0 Authentication Method Reference Values

List authentication method values for the AMR token claim.

OAuth 2.0 Authorization Framework: Bearer Token Usage

Describes how to use bearer tokens in HTTP requests to access OAuth 2.0 protected resources.

OAuth 2.0 for Native Apps

Security and usability best practice for OAuth usage in Native apps.

OAuth 2.0 Pushed Authorization Requests

Pushed authorization request (PAR) allows clients to push the payload of an OAuth 2.0 authorization request to the authorization server via a direct request.

OAuth 2.0 Mutual-TLS Client Authentication and Certificate-Bound Access Tokens

Standardizes enhanced security options for OAuth 2.0 utilizing client-certificate-based mutual TLS (mTLS).

OAuth 2.0 JWT-Secured Authorization Request (JAR)

Allows to send request parameters in a JSON Web Token (JWT), which can be signed with JSON Web Signature (JWS) and encrypted with JSON Web Encryption (JWE) so that the integrity, source authentication, and confidentiality properties of the authorization request are attained.

OpenID Connect Discovery 1.0

Mechanism for an OpenID Connect Relying Party to discover the End-User's OpenID Provider and obtain information needed to interact with it.

OpenID Connect Front-Channel Logout

Logout mechanism that uses front-channel communication via the User Agent between the OpenID Connect provider (OP) and Relying Parties (RPs) being logged out that does not need an OpenID Provider iframe on Relying Party pages.

OpenID Connect Back-Channel Logout

Logout mechanism that uses direct back-channel communication between the OpenID Connect provider (OP) and Relying Parties (RPs) being logged out.

OpenID Connect RP-Initiated Logout

Defines how a Relying Party can requests that the OpenID Connect provider log out the End-User by redirecting the End-User's User Agent to the OP's Logout Endpoint.

OAuth 2.0 Authorization Server Metadata

A metadata format that an OAuth 2.0 client can use to obtain the information needed to interact with an OAuth 2.0 authorization server.

OAuth 2.0 Token Revocation

Endpoint for OAuth authorization servers which allows clients to notify the authorization server that a previously obtained refresh or access token is no longer needed.

OAuth 2.0 Dynamic Client Registration Protocol

Defines how an OAuth 2.0 Relying Party (RP) can dynamically register with the OAuth 2.0 server provider.

OAuth 2.0 Demonstrating Proof of Possession (DPoP)

Demonstrates proof of possession of the client's private key for OAuth 2.0.

OpenID Connect Dynamic Client Registration

Mechanism for sender-constraining OAuth 2.0 tokens via a proof-of-possession mechanism on the application level which allows for the detection of replay attacks with tokens.

OAuth 2.0 Token Introspection

Method for a protected resource to query an OAuth 2.0 authorization server to determine the active state of an OAuth 2.0 token and to determine meta-information about this token.

OAuth 2.0 Rich Authorization Requests (RAR)

Extends OAuth 2.0 authorization requests with additional authorization_details parameter that allows clients to specify their fine-grained authorization requirements using the expressiveness of JSON data structures.

Financial-grade API Security Profile 1.0 - Part 1: Baseline

Baseline security profile of OAuth that is suitable for protecting APIs with a moderate inherent risk in the context of Financial-grade APIs.

Financial-grade API Security Profile 1.0 - Part 2: Advanced

Advanced security profile of OAuth that is suitable to be used for protecting APIs with high inherent risk in the context of Financial-grade APIs.

JWT Secured Authorization Response Mode for OAuth 2.0 (JARM)

JWT-based mode to encode OAuth authorization response parameters with additional claims used to further protect the transmission.

Initiating User Registration via OpenID Connect

Specifications for initiating user registration via OpenID Connect and create prompt.

OpenID Connect Session Management

Specifications about OpenID Connect session management.

OpenID Connect Client-Initiated Backchannel Authentication Flow - Core 1.0

Specifications for Client-Initiated Backchannel Authentication (CIBA) flow.

OpenID Provider Authentication Policy Extension 1.0

Specifications about a mechanism by which a Relying Party can request that particular authentication policies like multi-factor authentication be applied by the OpenID Provider.

JWT Response for OAuth Token Introspection

A signed additional JSON Web Token (JWT) secured response for OAuth 2.0 Token Introspection.

OAuth 2.0 Protected Resource Metadata

Metadata format that an OAuth 2.0 client or authorization server can use to obtain the information needed to interact with an OAuth 2.0 protected resource.

OAuth 2.0 Security Best Current Practice

Best security practice when using OAuth 2.0 and OpenID Connect.

OpenID Connect Extended Authentication Profile (EAP) ACR Values 1.0

Specifications for OpenID Connect Extended Authentication Profile (EAP) ACR Values which allows to request specific authentication methods and assurance levels.

Resource Indicators for OAuth 2.0

A mechanism that allows an OAuth 2.0 client to indicate the resource server that it intends to access.

OAuth 2.0 Authorization Server Issuer Identification

Defines a new iss parameter in the authorization response in order to identify the authorization server that issued the authorization response and mitigates mix-up attacks.

FAPI 2.0 Security Profile

New version of the FAPI security profile that is suitable for protecting APIs with a high inherent risk in the context of Financial-grade APIs.

FAPI 2.0 Attacker Model

Security goals, attacker models and security mechanisms for Financial-grade APIs.

FAPI 2.0 Message Signing

API security profile for signing and verifying certain FAPI 2.0 Security Profile based requests and responses.

OAuth Client ID Metadata Document

Mechanism through which an OAuth client can identify itself to authorization servers, without prior dynamic client registration or other existing registration.

OAuth 2.0 Dynamic Client Registration Management Protocol

Endpoints for management of OAuth 2.0 dynamic client registrations.

OpenID Connect Standard Claims Registration for CBOR Web Tokens

Defines how to represent the OpenID Connect standard claims in CBOR Web Tokens (CWTs).

OpenID Connect Federation 1.0

Draft specifications for putting in place bilateral federations between to organizations.

OpenID AuthZEN

Standardized API for requesting access decisions from an authorization service in order to ease integration between services.

Financial-grade API: Client Initiated Backchannel Authentication Profile

Financial services profile specifications for Client Initiated Backchannel Authentication (aka CIBA).

OAuth 2.0 for Browser-Based Apps

Security and usability best practice for OAuth usage in Browser-based apps.

Selective Disclosure for JWTs (SD-JWT)

Specification for selective disclosure of JWT elements.

OAuth 2.1

Consolidation of OAuth 2.0 specifications into a single document, removing deprecated features and clarifying best practices.

OAuth 2.0 App2App Browserless Flow

Describing a protocol enabling native navigation across apps performing authentication using the App2App pattern, without requiring a web browser.

OAuth 2.0 Attestation-Based Client Authentication

Extension to OAuth 2.0 enabling public clients to authenticate using key-bound attestations.

OpenID Shared Signals Framework Specification 1.0

Shared Signals Framework (SSF) enables sharing of signals and events between cooperating peers that enables multiple applications such as Risk Incident Sharing and Coordination (RISC) and the Continuous Access Evaluation Profile (CAEP).

Cross-App Access (XAA), formally known as the "Identity Assertion Authorization Grant"

Enables AI agents and apps to securely access and act across multiple services with user consent using standardized and fine-grained OAuth permissions.

OAuth Identity and Authorization Chaining Across Domains

Preserves user identity, authorization context, and call-chain history across multiple services and trust domains using OAuth token exchange and JWT-based assertions.

OAuth 2.0 for First-Party Applications

Defines the Authorization Challenge Endpoint to enable native applications to obtain user authorization through native user interfaces.

OpenID Connect for Agents (OIDC-A) 1.0

A research proposal (not a standard or IETF draft) extending OpenID Connect to support AI agent identity, attestation, delegation chains, and fine-grained authorization within the OAuth ecosystem.

OpenID

The OpenID Connect official website.

OAuth

The OAuth website maintained by Aaron Parecki which list different resources about the protocol.

ByteByteGo

Oauth 2.0 explains using visual and simple terms.

Aaron Parecki

OAuth WG Member blog posts about OAuth 2.0.

Alex Bilbie

Blog posts about OAuth 2.0 topic.

CerberAuth

A blog talking about OpenID Connect and OAuth 2.0.

Nacho

An OAuth 2.0 client creation helper helping to choose the right grant type depending on the application.

Curity Resources

Curity solution resources articles about OpenID Connect.

Okta Blog

Okta vendor blog posts about OAuth 2.0 and OpenID Connect.

Medium OAuth 2.0

Medium blog with learnings, patterns and ideas around use of OAuth 2.0.

Mike Jones: Self-Issued

Mike Jones blog posts about OAuth 2.0 and OpenID Connect.

IAMDevBox

Developer blog covering OAuth 2.0/2.1, OIDC, SAML, Keycloak, ForgeRock, and PingIdentity with hands-on tutorials and troubleshooting guides.

OAuth for Model Context Protocol

Aaron Parecki article about how OAuth works and how it should be used in the context of model context protocol (MCP) server.

OAuth common vulnerabilities

PortSwigger article about OAuth 2.0 common vulnerabilities and how to mitigate them.

MCP OAuth 2.1 Authentication: How AI Agents Securely Connect to Tools

How the Model Context Protocol uses OAuth 2.1 with mandatory PKCE, RFC 8707 audience binding, and zero-configuration discovery for AI agent authentication.

GitHub Actions OIDC – Non-Human Identities and Secretless Authentication

A two-part guide on moving from static secrets to OIDC-based identities in GitHub Actions, including a practical lab for protecting APIs.

OAuth.com Playground

OAuth 2.0 / OpenID Connect Playground with authorization flows and step by step of the process of obtaining an access token.

SecureAuthCorp/oauth2c

OAuth 2.0 and OpenID Connect command line client for testing and exploring different flows.

Curity Playground

Tools for exploring and testing OAuth and OpenID Connect flows.

MojoAuth: Passkey Playground

Build and visualize OpenID Connect requests with this interactive tool. Configure parameters, generate request URLs, and decode JWT tokens.

OAuth Mock Server

A free and open-source OAuth mock server that simulates the biggest providers just by replacing the URL. Useful for E2E testing.

2012 - Getting Started with OAuth 2.0 by Ryan Boyd

2018 - OAuth 2.0 Simplified by Aaron Parecki

2020 - The Little Book of OAuth 2.0 RFCs by Aaron Parecki

2021 - Keycloak - Identity and Access Management for Modern Applications: Harness the power of Keycloak, OpenID…

2022 - Solving Identity Management in Modern Applications: Demystifying OAuth 2, OpenID Connect, and SAML 2 by Yvonne…