{"slug":"best-self-hosted-oauth-and-openid-connect-servers","title":"Best self-hosted OAuth and OpenID Connect servers","question":"What are the best self-hosted OAuth and OpenID Connect servers in 2026?","verdict":"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).","category":"Auth","url":"https://modelsagree.com/best/best-self-hosted-oauth-and-openid-connect-servers","updated":"2026-09-04","models":["ChatGPT","Claude","Gemini","Grok"],"consensus":"All 4 models rank Keycloak the top pick","disagreement":null,"combined":[{"rank":1,"product":"Keycloak","domain":"keycloak.org","score":20,"appearances":4,"modelRanks":{"ChatGPT":1,"Claude":1,"Gemini":1,"Grok":1},"reason":"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."},{"rank":2,"product":"Zitadel","domain":"zitadel.com","score":13,"appearances":4,"modelRanks":{"ChatGPT":3,"Claude":2,"Gemini":3,"Grok":3},"reason":"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."},{"rank":3,"product":"authentik","domain":"goauthentik.io","score":12,"appearances":4,"modelRanks":{"ChatGPT":2,"Claude":4,"Gemini":4,"Grok":2},"reason":"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."},{"rank":4,"product":"Ory Hydra","domain":"ory.com","score":8,"appearances":3,"modelRanks":{"ChatGPT":5,"Claude":3,"Gemini":2},"reason":"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."},{"rank":5,"product":"FusionAuth","domain":"fusionauth.io","score":3,"appearances":2,"modelRanks":{"ChatGPT":4,"Gemini":5},"reason":"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."},{"rank":6,"product":"WSO2 Identity Server","domain":"wso2.com","score":1,"appearances":1,"modelRanks":{"Claude":5},"reason":"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."}],"perModel":{"ChatGPT":[{"rank":1,"product":"Keycloak","reason":"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.","fix":"Its configuration depth, JVM footprint, and clustering make it a poor set-and-forget choice for small teams."},{"rank":2,"product":"authentik","reason":"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.","fix":"Its large-scale and regulated-enterprise track record remains shallower than Keycloak’s."},{"rank":3,"product":"Zitadel","reason":"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.","fix":"Its AGPL-3.0 license is unsuitable for some proprietary embedding or redistribution without a commercial license."},{"rank":4,"product":"FusionAuth","reason":"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.","fix":"Custom OAuth scopes, SCIM, advanced MFA, and other important capabilities sit behind substantial paid tiers."},{"rank":5,"product":"Ory Hydra","reason":"An OpenID-certified, Apache-licensed, high-throughput OAuth 2.1/OIDC engine with excellent protocol coverage and complete control over login and consent UX.","fix":"It deliberately omits users, registration, and login UI, so teams must build or integrate those pieces; it is not a turnkey IdP."}],"Claude":[{"rank":1,"product":"Keycloak","reason":"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.","fix":"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."},{"rank":2,"product":"Zitadel","reason":"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.","fix":"Smaller ecosystem and fewer legacy protocol bridges (SAML/LDAP support is thinner and newer), so heterogeneous enterprise integration can hit gaps."},{"rank":3,"product":"Ory Hydra","reason":"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.","fix":"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."},{"rank":4,"product":"authentik","reason":"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.","fix":"Younger project with a smaller commercial-support footprint and less formal certification/hardening pedigree than Keycloak or Ory for regulated, high-assurance deployments."},{"rank":5,"product":"WSO2 Identity Server","reason":"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.","fix":"Enterprise complexity and resource weight; configuration and licensing/support model are cumbersome for small teams, and community momentum trails the lighter modern options."}],"Gemini":[{"rank":1,"product":"Keycloak","reason":"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.","fix":"Heavy operational complexity and high memory footprint make it cumbersome and over-engineered for teams seeking a minimal, lightweight token service."},{"rank":2,"product":"Ory Hydra","reason":"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.","fix":"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."},{"rank":3,"product":"Zitadel","reason":"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).","fix":"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."},{"rank":4,"product":"authentik","reason":"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).","fix":"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."},{"rank":5,"product":"FusionAuth","reason":"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.","fix":"Advanced capabilities such as enterprise IdP brokering, SCIM, and automated compliance features require proprietary paid licensing, making it unsuitable for strictly open-source deployments."}],"Grok":[{"rank":1,"product":"Keycloak","reason":"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.","fix":"JVM/ops tax and dated admin UX — not for a one-VPS homelab or a team that refuses to operate PostgreSQL + Infinispan upgrades."},{"rank":2,"product":"authentik","reason":"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.","fix":"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."},{"rank":3,"product":"Zitadel","reason":"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.","fix":"AGPL-3.0 since v3"}]},"missedByModel":{"ChatGPT":[{"product":"Logto","reason":"excellent modern UX, organizations, RBAC, MFA, and OSS value, but its self-hosted edition and production record are less mature"},{"product":"Curity Identity Server","reason":"exceptional standards and FAPI depth, but the useful supported feature set is sales-led and offers weaker value for the typical team"}],"Claude":[{"product":"Authelia","reason":"superb lightweight forward-auth/2FA companion for reverse proxies, but not a full standalone OAuth2/OIDC authorization server for third-party apps"},{"product":"Janssen","reason":"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":[{"product":"Authelia","reason":"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"},{"product":"Casdoor","reason":"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"}]}}