Apereo CAS vs WSO2 Identity Server
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 | WSO2 Identity Server |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 93 · Excellent | 80 · Excellent |
| Category | Identity & SSO | Identity & SSO |
| License | Apache-2.0 | Apache-2.0 |
| Language | Java | Java |
| Setup difficulty | Hard | Hard |
| Min. RAM | 1,024 MB | 4,096 MB |
| Deployment | docker, kubernetes, bare-metal | docker, kubernetes, bare-metal |
| GitHub stars | ★ 11,376 | ★ 880 |
| First released | 2004 | 2007 |
| Replaces | Okta, Ping Identity | Okta, ForgeRock |
What are Apereo CAS and WSO2 Identity Server?
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
WSO2 Identity Server
WSO2 Identity Server is an open-source IAM product that provides single sign-on, identity federation, and strong authentication. It supports SAML, OpenID Connect, and adaptive authentication policies.
- Single sign-on
- Identity federation
- Adaptive authentication
- Standards support
Apereo CAS vs WSO2 Identity Server: key differences
Both projects are written in Java. Apereo CAS is the lighter option, starting around 1,024 MB of RAM against 4,096 MB for WSO2 Identity Server. Apereo CAS is the more established project (first released 2004), while WSO2 Identity Server arrived in 2007. Apereo CAS has the considerably larger community, at 11,376 GitHub stars versus 880.
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 WSO2 Identity Server if…
- Enterprise feature set
- Strong standards coverage
Watch out for
- Resource heavy
- Complex tuning
Frequently asked questions
Is Apereo CAS or WSO2 Identity Server 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 WSO2 Identity Server free and open-source?
Yes. Apereo CAS is licensed under Apache-2.0 and WSO2 Identity Server under Apache-2.0. Both can be self-hosted at no software cost.
Can I run Apereo CAS and WSO2 Identity Server with Docker?
Apereo CAS: yes. WSO2 Identity Server: yes.
Which is lighter on resources, Apereo CAS or WSO2 Identity Server?
Apereo CAS has the smaller minimum footprint at 1,024 MB of RAM, compared to about 4,096 MB for WSO2 Identity Server. Real-world usage depends on library size, user count, and enabled features.