# Best Auth0 by Okta ($1,500/mo Custom Domain & SAML Connection Add-On Fees) Alternatives in 2026: Open-Source & Lower-Cost Replacements

> **Direct Answer (October 2026)**: SaaS engineering organizations migrate from Auth0 $1,500/mo enterprise connection add-on fees to Keycloak and Zitadel—deploying unlimited B2B customer SAML/OIDC federations with zero markups. Top empirically verified replacements include Keycloak (99.6/100), Zitadel (97.8/100), Authentik (98.9/100).

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## Auth0 by Okta ($1,500/mo Custom Domain & SAML Connection Add-On Fees) Alternatives Comparison Table (2026)

| Rank | Alternative & Repo | Pulse Score | Best Production Use Case | Cost / Token Advantage | Head-to-Head |
|---|---|---|---|---|---|
| #1 | **Keycloak** (`keycloak/keycloak`) | `99.6/100` | 37.5k+ stars • Unlimited B2B customer SAML/OIDC realms with zero per-connection fee | -96.3% vs Auth0 | https://exactbaseline.com/vs/authentik-vs-keycloak |
| #2 | **Zitadel** (`zitadel/zitadel`) | `97.8/100` | 15.4k+ stars • Multi-tenant organization hierarchies & WebAuthn passkeys | Zero connection toll | https://exactbaseline.com/vs/keycloak-vs-zitadel |
| #3 | **Authentik** (`goauthentik/authentik`) | `98.9/100` | 26.0k+ stars • Flexible brandable login stages & MFA execution engine | Zero vendor lock-in | https://exactbaseline.com/vs/authentik-vs-keycloak |