Best self-hosted OAuth and OpenID Connect server

Combined ranking

1. 1
   Keycloakkeycloak.org ↗—19 pts

   GPT #1Claude #1Gemini #2Grok #1

   The strongest all-round choice: mature OAuth 2.0/OIDC and SAML support, identity brokering, LDAP/AD federation, MFA/passkeys, fine-grained authorization, extensive customization, and a large operational knowledge base; best when broad standards coverage matters more than simplicity

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   GPT The strongest all-round choice: mature OAuth 2.0/OIDC and SAML support, identity brokering, LDAP/AD federation, MFA/passkeys, fine-grained authorization, extensive customization, and a large operational knowledge base; best when broad standards coverage matters more than simplicity

   Claude The default answer for a reason — CNCF-graduated, battle-tested at enterprise scale, and covers nearly everything out of the box: OIDC/OAuth2/SAML, user federation (LDAP/AD), identity brokering, fine-grained authorization, admin console, and a huge extension ecosystem; Red Hat backing (as build of RHBK) gives it long-term credibility, and the newer Quarkus-based distribution cut its historical resource bloat considerably. Assumption: the typical practitioner wants a full IdP, not just a protocol server.

   Grok Mature CNCF-backed enterprise standard with broadest protocol support (full OIDC, OAuth 2.0, SAML 2.0 IdP/SP, LDAP/AD federation, Kerberos), deep customization via SPIs, fine-grained authz (UMA), huge ecosystem/community, Red Hat support option, battle-tested at massive scale for typical self-hosted needs. Assumption: most practitioners value proven stability and integration breadth over minimalism.

   Gemini Battle-tested enterprise reliability with unmatched protocol support (SAML, LDAP, Kerberos, OIDC) and a massive plug-in community.

   Where it falls short

   per GPT Its realm model, configuration surface, upgrades, and production clustering create substantial administrative complexity for small teams

   per Claude Operational heaviness remains real — JVM footprint, clustering/upgrade complexity, and a sprawling admin model make it overkill for small teams who need only OIDC login for a few apps.

   per Gemini Extremely heavy JVM-based resource footprint and steep learning curve, making it ill-suited for low-resource hosting or simple projects.

2. 2
   ZITADELzitadel.com ↗—14 pts

   GPT #2Claude #2Gemini #3Grok #3

   A near-tie with Keycloak for cloud-native teams, combining polished OIDC/OAuth support, first-class organizations and multi-tenancy, passwordless authentication, strong APIs, auditability, and credible self-hosting; especially strong for B2B SaaS

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   GPT A near-tie with Keycloak for cloud-native teams, combining polished OIDC/OAuth support, first-class organizations and multi-tenancy, passwordless authentication, strong APIs, auditability, and credible self-hosting; especially strong for B2B SaaS

   Claude The strongest modern challenger — Go-based single binary, multi-tenancy as a first-class concept, event-sourced audit trail, passkeys/WebAuthn done well, solid APIs/Terraform support, and Apache-2.0 licensed with an optional commercial cloud; it delivers most of Keycloak's IdP surface with far less operational drag. Near-tie with Keycloak for greenfield SaaS builders; Keycloak wins on ecosystem maturity and enterprise federation depth.

   Gemini Built specifically for SaaS with first-class multi-tenancy (near-tie with Authentik, chosen over it if B2B multi-tenancy is the priority), event-sourced audit logs, and a modern Go-based API-first design.

   Grok Modern Go-based, lightweight, API-first (gRPC/REST), native multi-tenancy/organizations, event-sourced auditing, strong passkeys/MFA, excellent for cloud-native/K8s and B2B SaaS practitioners needing scalable, developer-friendly self-hosted OIDC.

   Where it falls short

   per GPT Event-sourced architecture and comparatively opinionated deployment make operating and troubleshooting it less familiar than conventional database-backed IAM

   per Claude Requires CockroachDB/Postgres and its event-sourcing model makes some customizations and data migrations less straightforward; the extension/community ecosystem is much smaller than Keycloak's.

   per Gemini Its rigid tenant-organization hierarchy adds unnecessary overhead and complexity for single-tenant or home lab deployments.

3. 3
   authentikgoauthentik.io ↗—13 pts

   GPT #3Claude #5Gemini #1Grok #2

   Offers an extremely flexible visual flow-builder architecture, comprehensive out-of-the-box user management, a modern admin UI, and a built-in reverse proxy provider.

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   Gemini Offers an extremely flexible visual flow-builder architecture, comprehensive out-of-the-box user management, a modern admin UI, and a built-in reverse proxy provider.

   Grok Excellent balance of modern polished UI, flexible flows/stages, strong proxy outposts for legacy/non-SSO apps, full OIDC/SAML/LDAP/SCIM support, easy self-hosting with good performance — ideal for growing teams and heterogeneous internal tool estates.

   GPT Excellent practitioner value for protecting self-hosted applications, with an approachable interface, flexible visual flows, OIDC/SAML, LDAP and proxy integrations, built-in outposts, and unusually good support for mixed modern and legacy apps

   Claude The best self-hosted option for homelab-to-mid-size deployments — genuinely pleasant admin UI, OIDC/SAML/LDAP/SCIM plus proxy-based auth for apps with no native SSO, flexible flow/policy engine, and painless Docker deployment; it has largely displaced older options in the self-hosting community on usability alone.

   Where it falls short

   per GPT It is less proven for very large, protocol-demanding CIAM deployments, and its moving configuration and upgrade surface can require hands-on care

   per Claude Weaker fit for large-enterprise or high-assurance use — smaller security track record and team than Keycloak/Red Hat, and its flow engine's flexibility can hide misconfiguration foot-guns.

   per Gemini Its highly abstract staging and policy system introduces steep configuration complexity, making it overkill for basic authentication needs.

4. 4
   Ory Hydraory.com ↗—8 pts

   GPT #5Claude #3Gemini #4Grok #4

   Best-in-class pure OAuth2/OIDC server — OpenID-certified, headless, stateless, horizontally scalable, and deliberately unopinionated about login/consent, which makes it ideal when you already own user management and want a hardened token engine; widely proven at very high request volumes.

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   Claude Best-in-class pure OAuth2/OIDC server — OpenID-certified, headless, stateless, horizontally scalable, and deliberately unopinionated about login/consent, which makes it ideal when you already own user management and want a hardened token engine; widely proven at very high request volumes.

   Gemini A highly performant, secure, and lightweight Go-based engine that focuses strictly on standard-compliant OAuth2/OIDC token issuance.

   Grok Highly composable, certified OAuth2/OIDC (Hydra), headless/modular design for custom UIs and developer-centric stacks, strong for API-heavy or microservices environments.

   GPT A security-focused, OpenID-certified, API-first OAuth 2.0/OIDC server that excels when engineers want a scalable authorization server embedded in a custom identity architecture; near-tied with FusionAuth for protocol-centric platforms

   Where it falls short

   per GPT It is deliberately headless and not a complete identity product, so login, consent, user management, recovery, and administration require additional Ory components or custom engineering

   per Claude It is NOT an identity provider — you must build (or bolt on Ory Kratos for) login, consent, registration, and user storage yourself, so total effort is much higher than an all-in-one for typical deployments.

   per Gemini It is strictly headless and provides no user database or authentication UI, requiring you to build or integrate these components yourself.

5. 5
   DDuende IdentityServer—2 pts

   GPT —Claude #4Gemini —Grok —

   The mature choice for .NET shops — OpenID-certified framework with deep protocol coverage (including token exchange, CIBA, DPoP tracking spec updates early), excellent documentation, and full control since it embeds in your own ASP.NET Core app rather than running as a black box. Assumption: ranked for practitioners in the .NET ecosystem; outside it, it doesn't apply.

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   Claude The mature choice for .NET shops — OpenID-certified framework with deep protocol coverage (including token exchange, CIBA, DPoP tracking spec updates early), excellent documentation, and full control since it embeds in your own ASP.NET Core app rather than running as a black box. Assumption: ranked for practitioners in the .NET ecosystem; outside it, it doesn't apply.

   Where it falls short

   per Claude Commercial license required beyond small-company/dev use, and it's a framework, not a product — no admin UI or user store; you build and maintain the hosting application yourself.

6. 6
   FusionAuthfusionauth.io ↗—2 pts

   GPT #4Claude —Gemini —Grok —

   A polished, developer-friendly self-hosted CIAM server with solid OAuth/OIDC implementation, convenient APIs and SDKs, tenant support, customizable login workflows, and simpler application integration than many enterprise IAM suites

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   GPT A polished, developer-friendly self-hosted CIAM server with solid OAuth/OIDC implementation, convenient APIs and SDKs, tenant support, customizable login workflows, and simpler application integration than many enterprise IAM suites

   Where it falls short

   per GPT Several capabilities organizations commonly want are commercial-edition features, making long-term cost and license boundaries a material consideration

7. 7
   Autheliaauthelia.com ↗—1 pts

   GPT —Claude —Gemini #5Grok —

   An incredibly lightweight, single-binary Go solution that integrates seamlessly with reverse proxies to secure applications using a simple YAML configuration.

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   Gemini An incredibly lightweight, single-binary Go solution that integrates seamlessly with reverse proxies to secure applications using a simple YAML configuration.

   Where it falls short

   per Gemini Lacks advanced user registration workflows and comprehensive OIDC customization APIs, making it unsuitable for customer-facing applications.

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Tracked by ModelsAgree · rank 1 = 5 pts … rank 5 = 1 pt · re-polled weekly