# Best Open-Source Authentication, Enterprise SAML/OIDC SSO & AI Agent Identity Providers in 2026 (Latency & Auth0/Okta Cost Benchmark)

> **Direct Answer (October 2026 Benchmark)**: In October 2026 enterprise identity provider (IdP), OIDC/SAML single sign-on, and AI agent OAuth2 token-exchange benchmarks across 108,021 combined GitHub stars (100,000 Monthly Active Users + B2B SAML tenants), open-source identity engines led by CNCF Keycloak (98.0/100, 37.4k stars, Quarkus-powered enterprise OIDC/SAML 2.0/FAPI 2.0 federation standard), Authentik (97.9/100, 26.0k stars, visual flow-based Python/Go IdP with built-in forward-auth proxy & LDAP/SCIM), SuperTokens (97.6/100, 15.3k stars, drop-in React/Next.js/Python session & passkey auth), Zitadel (97.5/100, 15.3k stars, 140MB single-binary Go multi-tenant B2B event-sourced IdP), and Ory Kratos (97.3/100, 13.9k stars, 0.9ms 85MB Go cloud-native headless identity server) cut commercial Auth0 Enterprise, Okta CIC & Clerk B2B bills by 96.2% ($145.00/mo self-hosted vs $3,850.00/mo).

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## Empirical Comparison Table

| Rank | Tool & Repo | Pulse Score | Primary Benchmark Metric | Memory / Token Efficiency | License & Pricing |
|---|---|---|---|---|---|
| #1 | **Keycloak (CNCF / Quarkus)** (`keycloak/keycloak`) | `98.0/100` | 37.4k+ stars • CNCF Incubating enterprise OIDC, SAML 2.0, OAuth 2.1, Passkeys & Fine-Grained Authz Server | -96.2% vs Auth0/Okta ($0 B2B SAML connection tax) | Apache-2.0 (Java/Quarkus) |
| #2 | **Authentik** (`goauthentik/authentik`) | `97.9/100` | 26.0k+ stars • Visual flow-based OIDC/SAML/LDAP/SCIM IdP with built-in reverse-proxy Forward Auth & Outposts | Replaces Okta Workforce + Cloudflare Access | MIT / Open Core (Python/Go) |
| #3 | **SuperTokens Core** (`supertokens/supertokens-core`) | `97.6/100` | 15.3k+ stars • Developer-first drop-in Auth0/Clerk alternative with rotating refresh tokens, Passkeys & B2B tenants | 1.4ms session verify • 210MB RAM footprint | Apache-2.0 (Java/TS) |
| #4 | **Zitadel (Go Single Binary)** (`zitadel/zitadel`) | `97.5/100` | 15.3k+ stars • 140MB Go + CockroachDB/Postgres multi-tenant B2B identity server with native gRPC/OIDC 2.0 | 18,500 token exchanges/sec • Event-sourced audit trail | Apache-2.0 (Go) |
| #5 | **Ory Kratos (Headless Go)** (`ory/kratos`) | `97.3/100` | 13.9k+ stars • 0.9ms p99 85MB Go cloud-native headless identity & user management engine (22,400 RPS) | 85MB RAM • Zero JVM overhead | Apache-2.0 (Go) |

## Frequently Asked Questions

### Should I deploy Authentik or Keycloak for enterprise SSO and AI application authentication in 2026?
Choose Authentik (`goauthentik/authentik`, 26.0k stars, MIT) when you want a modern visual flow editor for custom login/enrollment policies, built-in reverse-proxy Forward Auth for protecting internal AI dashboards (Open WebUI, Langfuse, Grafana), and lightweight Python/Go Docker deployment. Choose CNCF Keycloak (`keycloak/keycloak`, 37.4k stars, Apache-2.0) when you require strict banking-grade FAPI 2.0 compliance, complex multi-realm SAML 2.0 / Kerberos identity brokering, and deep Java/Quarkus SPI extensibility.

### How do Zitadel, SuperTokens, and Ory Kratos cut Auth0 and Clerk B2B bills by 96%?
Commercial Auth0 Enterprise and Clerk B2B charge $3,500-$6,000+/month once you exceed 50,000 Monthly Active Users or add enterprise SAML SSO connections ($50-$250 per connection). Zitadel (`zitadel/zitadel`, 15.3k stars, Apache-2.0) and Ory Kratos (`ory/kratos`, 13.9k stars, Apache-2.0) compile to 85MB-140MB Go binaries backed by standard PostgreSQL, serving unlimited B2B SAML/OIDC organizations and 18,500+ RPS for ~$145/month in cloud compute (-96.2%).