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Authentication 6 alternatives tracked

Open-source alternatives to Auth0

Auth0 is a popular Authentication tool. Teams often seek open-source alternatives for cost savings, data ownership, or avoiding vendor lock-in.

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The alternatives

keycloak

★ 34,155 Java Apache-2.0

Open Source Identity and Access Management For Modern Applications and Services

keycloak/keycloak Updated 2026-05-01

authelia

★ 27,665 Go Apache-2.0

The Single Sign-On Multi-Factor portal for web apps, now OpenID Certified™

authelia/authelia Updated 2026-05-01

authentik

★ 21,274 Python NOASSERTION

The authentication glue you need.

goauthentik/authentik Updated 2026-05-01

supertokens-core

★ 15,029 Java NOASSERTION

Open source alternative to Auth0 / Firebase Auth / AWS Cognito

supertokens/supertokens-core Updated 2026-04-24

zitadel

★ 13,665 Go AGPL-3.0

ZITADEL - Identity infrastructure, simplified for you.

zitadel/zitadel Updated 2026-04-30

kratos

★ 13,611 Go Apache-2.0

Headless cloud-native authentication and identity management written in Go. Scales to a billion+ users. Replace Homegrown, Auth0, Okta, Firebase with better UX and DX. Passkeys, Social Sign In, OIDC, Magic Link, Multi-Factor Auth, SMS, SAML, TOTP, and more. Runs everywhere, runs best on Ory Network.

ory/kratos Updated 2026-04-30

Comparison notes

OSS alternatives typically require self-hosting and operational effort in exchange for predictable cost and full data control. Feature parity varies — evaluate each option against your specific workflow before committing.

Migration tips

  • Export data from the SaaS before migration (most provide CSV/JSON exports)
  • Pilot the OSS alternative with a subset of your team before full rollout
  • Budget for self-hosting infrastructure and maintenance time

FAQ

Can I fully replace Auth0 with an OSS tool?

Feature parity varies. Most OSS alternatives cover 70-90% of core workflows, but may lack polish, integrations, or specialized features. Pilot the alternative with a subset of your team before fully committing.

What's the cost of self-hosting?

Plan for ~$5-50/month in VPS costs (DigitalOcean, Hetzner, etc.) plus 2-8 hours/month in maintenance. For a team of 20+, self-hosting usually breaks even against SaaS pricing within 6-12 months.

Which alternative should I pick?

Sort by GitHub stars (a proxy for community health), check the last-pushed date (avoid unmaintained projects), and read recent issues to gauge responsiveness.