Hanko
Passkey-first auth platform — SSO, MFA, and web components without vendor lock-in.
AGPL-3.0 alternative to Clerk and Auth0. Passkeys, OAuth, SAML, Hanko Elements UI, and self-hosted Go backend — or Hanko Cloud managed.
Auth0 is a widely used identity and authentication platform owned by Okta, offering hosted login, SSO, and MFA out of the box. It's easy to integrate, but it's closed source, and per-active-user pricing can climb quickly once an app has a real user base — plus your user data and login flow live on Auth0's infrastructure.
If you want passwordless, passkey-first authentication without depending on a third-party auth vendor, Hanko is an open-source option you can self-host.
FAQ
Is there a free, open-source alternative to Auth0?
Yes. Hanko is open source (AGPL-3.0) and can be self-hosted, avoiding Auth0's per-user pricing.
What's the best open-source alternative to Auth0?
Hanko is a strong pick if you want to move toward passkey-based, passwordless login rather than replicate Auth0's traditional username/password + social login setup feature-for-feature.
What are the top open-source alternatives to Auth0?
Browse all open-source alternatives to Auth0 above, or explore the full Developer Tools category for more options.