Best self-hosted OAuth and OpenID Connect servers
4 models · updated 2026-09-04
The verdict
Keycloak leads — All 4 models rank Keycloak the top pick.
As of 2026-09-04, ChatGPT, Claude, Gemini and Grok collectively rank Keycloak #1 for self-hosted oauth and openid connect servers on ModelsAgree — a unanimous pick. The models' case: Assuming a complete IdP is wanted, it offers the strongest all-round mix of OpenID-certified OIDC/OAuth, SAML, federation, passkeys, extensible authentication flows. The models' main caveat: Its configuration depth, JVM footprint, and clustering make it a poor set-and-forget choice for small teams. The strongest alternative is Zitadel — The strongest modern challenger — Go-based, cloud-native, built-in multi-tenancy, event-sourced audit trail, first-class OIDC/OAuth2 plus emerging. Source: https://modelsagree.com/best/best-self-hosted-oauth-and-openid-connect-servers (modelsagree.com, CC BY 4.0).
Combined ranking
- 1GPT #1Claude #1Gemini #1Grok #1
Assuming a complete IdP is wanted, it offers the strongest all-round mix of OpenID-certified OIDC/OAuth, SAML, federation, passkeys, extensible authentication flows, authorization services, organizations, and proven high-availability scaling.
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GPT Assuming a complete IdP is wanted, it offers the strongest all-round mix of OpenID-certified OIDC/OAuth, SAML, federation, passkeys, extensible authentication flows, authorization services, organizations, and proven high-availability scaling.
Claude The reference-grade open-source IAM server — full OAuth 2.0/2.1, OIDC (certified), SAML, token exchange, fine-grained authorization, user federation (LDAP/AD), brokering, and a deep SPI extension model that lets you customize nearly anything; huge community, Red Hat/CNCF backing, and battle-tested at enterprise scale make it the safe default.
Gemini Comprehensive enterprise feature set including out-of-the-box LDAP/Active Directory federation, multi-realm management, fine-grained authorization services, and certified OIDC/OAuth 2.0 implementations backed by immense production battle-testing; assumed the typical practitioner needs a complete, batteries-included identity provider rather than a standalone protocol engine.
Grok Broadest production-ready OIDC/OAuth 2.0 + SAML + LDAP/AD/Kerberos surface under Apache 2.0 and CNCF governance; Quarkus-era 26.x is the default when auditors, federation, fine-grained authorization, and a huge adapter ecosystem matter more than a pretty admin UI. Assumption: the typical practitioner needs a full IdP they can still run in ten years, not a homelab-only SSO box.
Where it falls shortper GPT Its configuration depth, JVM footprint, and clustering make it a poor set-and-forget choice for small teams.
per Claude Heavyweight JVM footprint and a steep operational/upgrade curve (theme, SPI, and realm-migration friction); overkill for a small app that just needs a token issuer.
per Gemini Heavy operational complexity and high memory footprint make it cumbersome and over-engineered for teams seeking a minimal, lightweight token service.
per Grok JVM/ops tax and dated admin UX — not for a one-VPS homelab or a team that refuses to operate PostgreSQL + Infinispan upgrades.
- 2GPT #3Claude #2Gemini #3Grok #3
The strongest modern challenger — Go-based, cloud-native, built-in multi-tenancy, event-sourced audit trail, first-class OIDC/OAuth2 plus emerging FIDO2/passkey and session-management support, and a clean API/Terraform-driven config that suits GitOps shops; far lighter to run than Keycloak with better DX.
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Claude The strongest modern challenger — Go-based, cloud-native, built-in multi-tenancy, event-sourced audit trail, first-class OIDC/OAuth2 plus emerging FIDO2/passkey and session-management support, and a clean API/Terraform-driven config that suits GitOps shops; far lighter to run than Keycloak with better DX.
GPT The strongest B2B SaaS design, combining first-class organizations, delegated administration, tenant-specific federation and policies, passkeys, service accounts, exhaustive APIs, and stateless horizontal scaling; nearly tied with authentik.
Gemini Cloud-native, turnkey IAM written in Go tailored for multi-tenancy and modern B2B SaaS, featuring clean gRPC/REST APIs, event-sourced audit trails, and self-service organization management with far easier administration than legacy enterprise platforms (near-tie with Authentik).
Grok Strongest native multi-tenant/B2B model (organizations + instances), API-first gRPC/REST, event-sourced audit, OIDC + SAML + passkeys in a Go binary that maps to SaaS product identity rather than a corporate directory. Assumption: the practitioner is building a product other orgs log into, not only protecting internal apps.
Where it falls shortper GPT Its AGPL-3.0 license is unsuitable for some proprietary embedding or redistribution without a commercial license.
per Claude Smaller ecosystem and fewer legacy protocol bridges (SAML/LDAP support is thinner and newer), so heterogeneous enterprise integration can hit gaps.
per Gemini Its event-sourced database requirements (PostgreSQL or CockroachDB) demand specific operational expertise and tuning, making it mismatched for simple single-node deployments or embedded SQLite use cases.
per Grok AGPL-3.0 since v3
- 3GPT #2Claude #4Gemini #4Grok #2
The best usability-to-capability balance for self-hosted SSO, with polished flows, OIDC/OAuth, SAML, LDAP, SCIM, proxy outposts, passkeys, and current OpenID certification; a near-tie with ZITADEL, winning for mixed internal and legacy applications.
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GPT The best usability-to-capability balance for self-hosted SSO, with polished flows, OIDC/OAuth, SAML, LDAP, SCIM, proxy outposts, passkeys, and current OpenID certification; a near-tie with ZITADEL, winning for mixed internal and legacy applications.
Grok Best day-to-day self-hosted IdP for mixed estates: certified-class OIDC/OAuth plus SAML, LDAP/RADIUS outposts, proxy/forward-auth, passkeys, SCIM, and a flow builder that actually ships without a Java specialist. MIT core, Docker/K8s first, the option most teams finish configuring.
Claude Excellent self-hosted balance of power and usability — a visual, flexible flow/policy engine, OIDC/OAuth2/SAML/LDAP/proxy-forward-auth outlets, strong passkey/MFA support, and a friendly admin UI that homelabbers and mid-size teams adopt quickly; Docker-native and actively developed.
Gemini Highly versatile all-in-one identity provider with customizable execution flows, native forward-auth reverse-proxy integrations, and intuitive administration, making it exceptionally effective for securing internal infrastructure and mixed application environments (near-tie with Zitadel).
Where it falls shortper GPT Its large-scale and regulated-enterprise track record remains shallower than Keycloak’s.
per Claude Younger project with a smaller commercial-support footprint and less formal certification/hardening pedigree than Keycloak or Ory for regulated, high-assurance deployments.
per Gemini Distributed multi-service architecture (Python worker, Go core, Redis, PostgreSQL) introduces more moving parts and higher token-issuance latency under heavy load compared to compiled single-purpose binaries.
per Grok Heavier than Authelia (~2 GB class) and open-core on some enterprise bits — not for the smallest footprint or shops that must stay 100% OSI with zero paid modules.
- 4GPT #5Claude #3Gemini #2Grok —
Premier certified, headless OAuth 2.0 and OpenID Connect engine written in Go; delivers extreme throughput, minimal latency, and zero protocol compromise by strictly handling token issuance and consent while letting developers retain complete control over their user databases and UI.
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Gemini Premier certified, headless OAuth 2.0 and OpenID Connect engine written in Go; delivers extreme throughput, minimal latency, and zero protocol compromise by strictly handling token issuance and consent while letting developers retain complete control over their user databases and UI.
Claude The best pick when you want a certified, stateless, API-first OAuth2/OIDC provider (Hydra) that you compose with your own login/consent UI and pair with Kratos for identity; extremely scalable, security-focused, and cleanly decoupled — ideal for teams that treat auth as infrastructure.
GPT An OpenID-certified, Apache-licensed, high-throughput OAuth 2.1/OIDC engine with excellent protocol coverage and complete control over login and consent UX.
Where it falls shortper GPT It deliberately omits users, registration, and login UI, so teams must build or integrate those pieces; it is not a turnkey IdP.
per Claude Hydra is deliberately not a full IdP (no user management on its own), so you assemble multiple components and build UI yourself — high integration burden, wrong for those wanting turnkey.
per Gemini Comes with no built-in user directory, authentication UI, or credential storage, making it unsuitable for teams seeking a turnkey, plug-and-play identity platform.
- 5GPT #4Claude —Gemini #5Grok —
A mature, developer-friendly CIAM server with complete OAuth/OIDC and SAML support, strong REST APIs, Kickstart automation, migration tooling, customizable hosted journeys, tenants, and a useful unlimited Community edition.
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GPT A mature, developer-friendly CIAM server with complete OAuth/OIDC and SAML support, strong REST APIs, Kickstart automation, migration tooling, customizable hosted journeys, tenants, and a useful unlimited Community edition.
Gemini Polished, single-artifact customer identity and access management (CIAM) platform offering fast deployment, low resource consumption, extensive developer SDKs, and deep tenant isolation out of the box.
Where it falls shortper GPT Custom OAuth scopes, SCIM, advanced MFA, and other important capabilities sit behind substantial paid tiers.
per Gemini Advanced capabilities such as enterprise IdP brokering, SCIM, and automated compliance features require proprietary paid licensing, making it unsuitable for strictly open-source deployments.
- 6GPT —Claude #5Gemini —Grok —
Deep, standards-heavy enterprise IdP — extensive OAuth2/OIDC/SAML/WS-Fed/SCIM, adaptive/step-up MurthenAuthN, strong API management lineage, and mature governance/audit features that suit large regulated organizations needing broad protocol coverage with commercial support.
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Claude Deep, standards-heavy enterprise IdP — extensive OAuth2/OIDC/SAML/WS-Fed/SCIM, adaptive/step-up MurthenAuthN, strong API management lineage, and mature governance/audit features that suit large regulated organizations needing broad protocol coverage with commercial support.
Where it falls shortper Claude Enterprise complexity and resource weight; configuration and licensing/support model are cumbersome for small teams, and community momentum trails the lighter modern options.
Just missed the top 5
GPT Logto — excellent modern UX, organizations, RBAC, MFA, and OSS value, but its self-hosted edition and production record are less mature · Curity Identity Server — exceptional standards and FAPI depth, but the useful supported feature set is sales-led and offers weaker value for the typical team
Claude Authelia — superb lightweight forward-auth/2FA companion for reverse proxies, but not a full standalone OAuth2/OIDC authorization server for third-party apps · Janssen — Gluu's CNCF successor — highly standards-complete and enterprise-grade, but operationally complex and less mature/adopted than Keycloak, so it just edges out of the list
Gemini Authelia — outstanding reverse-proxy authentication companion, but missed because its full-featured OAuth/OIDC authorization server capabilities and client-management tooling are narrower than dedicated IdPs · Casdoor — fast setup and modern UI, but missed due to a less established enterprise security track record and fewer hardened production deployments compared to top picks
By model
ChatGPT
- 1.Keycloak
- 2.authentik
- 3.Zitadel
- 4.FusionAuth
- 5.Ory Hydra
Claude
- 1.Keycloak
- 2.Zitadel
- 3.Ory Hydra
- 4.authentik
- 5.WSO2 Identity Server
Gemini
- 1.Keycloak
- 2.Ory Hydra
- 3.Zitadel
- 4.authentik
- 5.FusionAuth
Grok
- 1.Keycloak
- 2.authentik
- 3.Zitadel
Common questions
What is the best self-hosted oauth and openid connect servers according to AI models?
Keycloak leads. All 4 models rank Keycloak the top pick. The current top 3: Keycloak, Zitadel, authentik. Ranked by asking ChatGPT, Claude, Gemini, Grok the same buying question and merging their top-5 picks, updated 2026-09-04. Source: modelsagree.com.
Which self-hosted oauth and openid connect servers did each AI model pick first?
ChatGPT: Keycloak. Claude: Keycloak. Gemini: Keycloak. Grok: Keycloak.
How is this self-hosted oauth and openid connect servers ranking made?
ChatGPT, Claude, Gemini, Grok are each asked the same buying question in a fresh session with no system steering. Their top-5 answers are merged (rank 1 = 5 pts … rank 5 = 1 pt) into the consensus ranking, re-polled on demand and tracked over time.
More on how polling works: full methodology →
Cite this ranking
ModelsAgree, “Best self-hosted OAuth and OpenID Connect servers” — merged ranking from ChatGPT, Claude, Gemini & Grok, polled 2026-09-04. https://modelsagree.com/best/best-self-hosted-oauth-and-openid-connect-servers (CC BY 4.0)
Tracked by ModelsAgree · rank 1 = 5 pts … rank 5 = 1 pt · re-polled on demand