SHSelfHostIndex

Apereo CAS vs Keycloak

A side-by-side comparison of two self-hosted identity & sso options — licensing, setup difficulty, resource needs, and what each one replaces.

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AP Apereo CAS Enterprise single sign-on server for web applications VS Keycloak Open-source identity and access management for modern apps
FeatureApereo CASKeycloak
Deploy effortUnder-an-hour setupUnder-an-hour setup
Health score93 · Excellent99 · Excellent
CategoryIdentity & SSOIdentity & SSO
LicenseApache-2.0Apache-2.0
LanguageJavaJava
Setup difficultyHardHard
Min. RAM1,024 MB1,024 MB
Deploymentdocker, kubernetes, bare-metaldocker, kubernetes, bare-metal
GitHub stars★ 11,376★ 36,967
First released20042014
ReplacesOkta, Ping IdentityOkta, Auth0, Microsoft Entra ID

What are Apereo CAS and Keycloak?

Apereo CAS

Apereo CAS is an open-source, enterprise single sign-on solution and identity provider. Widely used in higher education, it supports the CAS protocol along with SAML, OAuth2 and OpenID Connect.

  • CAS, SAML, OAuth2 and OIDC protocols
  • Multi-factor authentication
  • Pluggable authentication handlers
  • Delegated and federated authentication

Read the full Apereo CAS guide →

Keycloak

Keycloak is an enterprise-grade identity and access management solution backed by Red Hat. It provides single sign-on, identity brokering, social login and fine-grained authorization for applications and services.

  • SSO with OpenID Connect and SAML 2.0
  • Identity brokering and social login
  • User federation with LDAP and Active Directory
  • Fine-grained authorization services

Read the full Keycloak guide →

Apereo CAS vs Keycloak: key differences

Both projects are written in Java. Apereo CAS is the more established project (first released 2004), while Keycloak arrived in 2014. Keycloak has the considerably larger community, at 36,967 GitHub stars versus 11,376.

Why pick each one

Choose Apereo CAS if…

  • Mature SSO with broad protocol support
  • Widely adopted in academia

Watch out for

  • Configuration is involved
Apereo CAS details

Choose Keycloak if…

  • Mature and battle-tested
  • Strong enterprise feature set

Watch out for

  • Steep learning curve
  • Resource intensive
Keycloak details

Frequently asked questions

Is Apereo CAS or Keycloak better?

Neither is universally better. Keycloak has the larger community; both share a hard setup difficulty, so the decision comes down to features and licensing.

Are Apereo CAS and Keycloak free and open-source?

Yes. Apereo CAS is licensed under Apache-2.0 and Keycloak under Apache-2.0. Both can be self-hosted at no software cost.

Can I run Apereo CAS and Keycloak with Docker?

Apereo CAS: yes. Keycloak: yes.

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