5 Open-Source Auth0 Alternatives You Can Self-Host (2026)
Auth0 Essentials starts at $23/month for up to 1,000 monthly active users. Beyond that, the pricing scales by MAU in a way that surprises teams that grow: 10,000 MAUs cost roughly $240/month, and adding enterprise features (SAML, custom domains, MFA) pushes you to higher tiers. A self-hosted identity provider on a Liquid Web 4–8 GB Managed VPS eliminates per-MAU pricing entirely.
Auth0 provides OAuth2, OIDC, SAML, social login, MFA, and machine-to-machine auth in a single managed platform. All five tools below cover the same protocol surface — OIDC and OAuth2 at minimum, SAML and LDAP on most — with no per-user or per-application fees. The main trade-off is operational ownership: you manage upgrades, backups, and availability.
1. Authentik (MIT + Enterprise, ★ ~15k)
Authentik is the most approachable self-hosted identity provider for teams coming from Auth0. It covers OIDC, OAuth2, SAML, LDAP, SCIM, and passkeys in a single Docker Compose deployment, with a polished admin UI that guides you through creating applications and providers without requiring deep IAM expertise. Its flow-based architecture — where authentication sequences are configured as visual pipelines — makes it unusually flexible for custom MFA steps, account linking, and enrollment workflows.
For teams self-hosting their app stack and needing SSO across internal tools (Outline, Plane, Coolify, Gitea), Authentik is the recommended starting point. The MIT license covers the core; enterprise features (policy engine extensions, support SLAs) are available under a commercial license.
Key features:
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OIDC, OAuth2, SAML, LDAP, SCIM — full protocol coverage
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Passkeys and WebAuthn MFA built in
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Social login (GitHub, Google, Discord, and more) via OAuth2 providers
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Outpost proxies for protecting apps that don't support OIDC natively
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Low footprint: ~800 MB idle on a 4 GB VPS (server + worker + PostgreSQL + Redis)
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Stars: ~15k · License: MIT (core) · VPS recommended: 4 GB
2. Keycloak (Apache-2.0, ★ ~26k)
Keycloak is the enterprise-grade benchmark for self-hosted identity management. Red Hat backs it, and it powers authentication at Fortune 500 companies and government agencies. It covers every protocol Auth0 does (OIDC, OAuth2, SAML, LDAP/AD federation, Kerberos) plus a deep user federation model, client policies, fine-grained authorization, and an admin CLI that supports infrastructure-as-code deployments.
The honest trade-off: Keycloak is heavy and has a steep learning curve. It's Java-based and idles at 1–2 GB RAM on its own before your PostgreSQL and Redis containers — making an 8 GB VPS the comfortable minimum. Configuration is verbose and the admin UI rewards users who've spent time with the documentation.
For teams with enterprise SSO requirements (AD/LDAP federation, complex SAML integrations, multi-realm setups), Keycloak's depth and Red Hat's backing make it the right choice. For most startup and mid-size teams, Authentik delivers equivalent daily functionality with less operational friction.
- Stars: ~26k · License: Apache-2.0 · VPS recommended: 8 GB (Java, moderate–heavy)
- Official docs: keycloak.org/documentation
3. Pocket ID (BSD-2-Clause, ★ ~7.7k)
Pocket ID is an ultra-lightweight OIDC provider built around a passkey-first philosophy: no passwords, just WebAuthn. If your users authenticate with passkeys (platform authenticators, hardware security keys, or device biometrics), Pocket ID deploys in a single container and idles at roughly 256 MB. It covers the OIDC Authorization Code flow and supports multiple applications behind a single provider.
The trade-off is intentional scope limitation: Pocket ID does not support SAML, LDAP federation, or password-based authentication. For teams protecting internal tools where all users can be onboarded to passkeys, this is the cleanest possible deployment. For anything requiring password fallback, SAML connectors, or LDAP sync, use Authentik or Keycloak instead.
- Stars: ~7.7k · License: BSD-2-Clause · VPS recommended: 512 MB–1 GB (single binary)
- Official docs: pocket-id.org
4. Zitadel (Apache-2.0, ★ ~10k)
Zitadel is a modern Go-based identity platform that positions itself as a cloud-native alternative to both Auth0 and Keycloak. It supports OIDC, OAuth2, SAML, and a built-in user management API, with an "organizations" concept that maps well to multi-tenant SaaS products — you can model customer organizations as first-class entities with their own user pools, policies, and SSO configurations.
Compared to Keycloak, Zitadel is lighter (Go versus Java), faster to configure for standard use cases, and ships a cleaner API surface. Compared to Authentik, it has more mature multi-tenancy support but a less flexible flow system for custom authentication steps. For teams building a multi-tenant application where each customer needs their own SSO configuration, Zitadel's organization model is the most natural fit in this list.
- Stars: ~10k · License: Apache-2.0 · VPS recommended: 4–8 GB
- Official docs: zitadel.com/docs
5. SuperTokens (Apache-2.0, ★ ~14k)
SuperTokens is a different paradigm from the other tools in this list: instead of a standalone identity server you point applications at, SuperTokens ships as an SDK that embeds authentication directly into your application's API layer. You run a SuperTokens core service alongside your app, and the SDK handles sessions, token refresh, MFA, and social login — with the UI components living in your application's frontend.
This makes SuperTokens a strong choice for teams building a new application from scratch who want full UI control over the auth flow. It's less suited to the "add SSO to existing apps" use case that Auth0, Authentik, and Keycloak handle well.
- Stars: ~14k · License: Apache-2.0 · VPS recommended: 2–4 GB
- Official docs: supertokens.com/docs
Comparison table
| Tool | Best for | License | Idle RAM | Protocol coverage |
|---|---|---|---|---|
| Authentik | General-purpose SSO, internal tools | MIT (core) | ~800 MB | OIDC, OAuth2, SAML, LDAP, SCIM, passkeys |
| Keycloak | Enterprise SSO, AD/LDAP federation | Apache-2.0 | 1–2 GB | Full enterprise + Kerberos |
| Pocket ID | Passkey-only internal SSO | BSD-2-Clause | ~256 MB | OIDC only |
| Zitadel | Multi-tenant SaaS identity | Apache-2.0 | ~600 MB | OIDC, OAuth2, SAML |
| SuperTokens | Embedded app auth (SDK model) | Apache-2.0 | ~300 MB | Session auth + social login |
Prices subject to change — verify Auth0 pricing at auth0.com/pricing and Liquid Web at liquidweb.com/vps-hosting/managed-vps/.
Which tool should you choose?
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Replacing Auth0 for internal tooling SSO: Start with Authentik. It has the best onboarding experience and covers every protocol your internal apps need.
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Enterprise requirements (AD federation, complex SAML, multi-realm): Use Keycloak. Its depth justifies the heavier footprint and steeper learning curve.
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Passkey-first teams, minimal operational overhead: Use Pocket ID. Nothing simpler exists for OIDC-capable apps.
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Multi-tenant SaaS product: Evaluate Zitadel — its organization model is purpose-built for this.
Authentik supports both. Its outpost proxy can protect any web application, and its OIDC/OAuth2 provider works with any application that supports standard OAuth2 flows — including mobile apps, SPAs, and third-party SaaS tools. Teams use it for internal dashboards, developer tools, and customer-facing application authentication. The main constraint is that Authentik's UI is designed for admins, not end-users — the login pages are functional but require theming effort to match a consumer-grade experience.
This is the most important trade-off. Auth0's SLA guarantees uptime that a self-hosted single-server deployment cannot match without additional infrastructure (load balancer, standby replica, automated failover). For internal tooling, a well-maintained Liquid Web Managed VPS with daily backups is typically sufficient. For customer-facing auth where an outage locks out all users, either deploy Authentik or Keycloak in a high-availability configuration across multiple nodes, or keep Auth0 and use self-hosted identity only for internal tooling.
Yes. Authentik supports the OAuth2 Client Credentials flow for M2M authentication, where a service authenticates using a client ID and secret rather than a user login. Configure a Service Account application in Authentik with the Client Credentials grant type. This covers the same use case as Auth0 M2M tokens for API-to-API communication.