Apereo CAS vs OpenUnison
A side-by-side comparison of two self-hosted identity & sso options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | Apereo CAS | OpenUnison |
|---|---|---|
| Deploy effort | Under-an-hour setup | Read-the-docs project |
| Health score | 93 · Excellent | 67 · Good |
| Category | Identity & SSO | Identity & SSO |
| License | Apache-2.0 | Apache-2.0 |
| Language | Java | Less |
| Setup difficulty | Hard | Hard |
| Min. RAM | 1,024 MB | 1,024 MB |
| Deployment | docker, kubernetes, bare-metal | kubernetes, helm |
| GitHub stars | ★ 11,376 | ★ 136 |
| First released | 2004 | 2018 |
| Replaces | Okta, Ping Identity | Okta |
What are Apereo CAS and OpenUnison?
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
OpenUnison
OpenUnison is an open-source identity manager and single sign-on portal that integrates Kubernetes and applications with enterprise identity providers. It is self-hosted in the cluster.
- Kubernetes SSO portal
- Identity provisioning
- LDAP and SAML integration
- Self-service workflows
Apereo CAS vs OpenUnison: key differences
Apereo CAS is written in Java, while OpenUnison is built with Less. Apereo CAS is the more established project (first released 2004), while OpenUnison arrived in 2018. Apereo CAS has the considerably larger community, at 11,376 GitHub stars versus 136. Apereo CAS lists first-class Docker deployment; OpenUnison does not.
Why pick each one
Choose Apereo CAS if…
- Mature SSO with broad protocol support
- Widely adopted in academia
Watch out for
- Configuration is involved
Choose OpenUnison if…
- Released under the Apache-2.0 license
- Kubernetes-ready with Helm charts available
- Written in Less
Frequently asked questions
Is Apereo CAS or OpenUnison better?
Neither is universally better. Apereo CAS has the larger community; both share a hard setup difficulty, so the decision comes down to features and licensing.
Are Apereo CAS and OpenUnison free and open-source?
Yes. Apereo CAS is licensed under Apache-2.0 and OpenUnison under Apache-2.0. Both can be self-hosted at no software cost.
Can I run Apereo CAS and OpenUnison with Docker?
Apereo CAS: yes. OpenUnison: check the project docs for container support.