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Most buyers should pick Keycloak.
Choose Keycloak if you can self-host and want open-source identity software with no user or seat limits published. Choose Auth0 if its listed enterprise SSO, adaptive security, and machine-identity features fit your needs. Auth0 Essentials is $35/month and lists 500 monthly active users; its Free plan lists 25,000. Keycloak has no listed software fee, but the published pricing information does not state hosting or support costs.
01Side by side
| Auth0 | Keycloak | |
|---|---|---|
| Paid starting price | $35/month for Essentials; Free plan also available | Free to download; hosting price not published |
| Free plan | Free; up to 25,000 monthly active users | Open-source software free to download and use |
| Best for | Teams needing listed enterprise and adaptive-security features | Teams comfortable self-hosting open-source identity software |
| Core strength | Adaptive security, enterprise SSO, and machine identity | Self-hosted SSO, federation, and authorization |
| Learning curve | Ease-of-use review score: 7/10 | Ease-of-use review score: 5/10 |
| Integrations and data | Enterprise connections, SCIM, and organizations | OIDC, SAML, LDAP, and Active Directory |
| Team and seat costs | MAU caps; some add-on prices not published | No user or seat limits published; hosting unpriced |
| Support | Review support score: 5/10 | Review support score: 5/10 |
Auth0 Choose Auth0 if
- Choose Auth0 if you need its listed enterprise SSO and SCIM features.
- Choose Auth0 if adaptive MFA and bot detection are priorities.
- Choose Auth0 if machine authentication and AI agent identity matter.
Keycloak Choose Keycloak if
- Choose Keycloak if you can self-host identity software.
- Choose Keycloak if open-source software without published seat limits suits you.
- Choose Keycloak if LDAP, Active Directory, OIDC, or SAML connections fit.
02Pricing compared
Keycloak lists no software fee: it is free to download and use under the Apache License 2.0. But the published pricing information does not state hosting or support costs, so “free” does not establish the total cost of running it.
Auth0’s Free plan lists up to 25,000 monthly active users (MAUs). Essentials is $35 per month and lists up to 500 MAUs; Professional is $240 per month and also lists up to 500. That makes the Free plan’s published MAU cap higher than either paid tier’s listed cap. Confirm the limits that apply to your use case before switching. Enterprise pricing is custom. Annual prices and add-on prices are not published on the vendor's site.
03Features and depth
Auth0’s feature list covers passwordless and social login, adaptive MFA, bot detection, enterprise SSO, SCIM, and permissions for users, AI agents, and RAG data. It also lists Client Credentials and short-lived tokens for machine authentication. Auth for MCP, Adaptive MFA, Bot Detection, and other security options appear among its add-ons; prices are not published, so check what your chosen plan includes.
Keycloak’s listed features include single sign-on, social login, identity brokering with OpenID Connect or SAML providers, and user federation with LDAP and Active Directory. Its admin console manages users, applications, identity providers, and authorization policies. Both products list fine-grained authorization, but the published Keycloak information does not list Auth0’s specific AI-agent identity or MCP features. Keycloak’s feature list also does not publish user or seat limits.
04Ease of use and learning curve
Keycloak is the better fit if your team is prepared to self-host and manage identity through its consoles. The published review describes it as flexible but says to skip it if the simplest setup is the priority; its ease-of-use score is 5 out of 10.
Auth0’s review gives it 7 out of 10 for ease of use, but that does not remove the need to check MAU caps, plan coverage, and add-on prices. The published information does not compare setup steps or migration effort. In practice, the key decision from these materials is whether you want self-hosted software with hosting costs not stated, or Auth0’s listed plans and limits.
Questions people ask
What's the difference between OAuth and Auth0?
The published product information does not define OAuth. It describes Auth0 as an identity platform for managing logins and access across websites, apps, and APIs. So this comparison treats Auth0 as a product, but does not provide enough information to compare its implementation with OAuth itself.
Why is Keycloak so complicated?
The published review flags simplicity as a reason to skip Keycloak, and gives it an ease-of-use score of 5 out of 10. Keycloak is described as self-hosted software with centralized admin and account-management consoles; the published information does not detail setup steps or explain exactly which parts users find difficult.
Is there a free version of Auth0?
Yes. Auth0’s pricing information lists a Free plan at $0 per month for up to 25,000 monthly active users, one custom domain, five organizations, one enterprise connection, and one tenant. Check the published limits against your needs; paid-plan caps and add-on prices differ or are not published.
Is Keycloak using OAuth?
The published Keycloak feature information lists connections to OpenID Connect or SAML identity providers, but it does not explicitly state OAuth support. We can’t confirm that point from these materials alone. Check Keycloak’s current documentation for the specific protocol and configuration you need.