Apereo CAS vs SimpleSAMLphp
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 | SimpleSAMLphp |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 93 · Excellent | 83 · Excellent |
| Category | Identity & SSO | Identity & SSO |
| License | Apache-2.0 | LGPL-2.1 |
| Language | Java | PHP |
| Setup difficulty | Hard | Medium |
| Min. RAM | 1,024 MB | 256 MB |
| Deployment | docker, kubernetes, bare-metal | bare-metal, source, docker |
| GitHub stars | ★ 11,374 | ★ 1,141 |
| First released | 2004 | 2007 |
| Replaces | Okta, Ping Identity | Okta, PingFederate |
What are Apereo CAS and SimpleSAMLphp?
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
SimpleSAMLphp
SimpleSAMLphp is a widely used PHP application for implementing SAML 2.0 identity and service providers. It enables web single sign-on and federation for PHP environments and beyond.
- SAML 2.0 IdP and SP
- Identity federation
- Many auth backends
- Module ecosystem
Apereo CAS vs SimpleSAMLphp: key differences
Apereo CAS is written in Java, while SimpleSAMLphp is built with PHP. Licensing differs — Apache-2.0 for Apereo CAS versus LGPL-2.1 for SimpleSAMLphp. SimpleSAMLphp is the lighter option, starting around 256 MB of RAM against 1,024 MB for Apereo CAS. Apereo CAS is the more established project (first released 2004), while SimpleSAMLphp arrived in 2007. Apereo CAS has the considerably larger community, at 11,374 GitHub stars versus 1,141.
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 SimpleSAMLphp if…
- Proven and widely deployed
- Flexible modules
Watch out for
- Configuration is intricate
- PHP performance limits
Frequently asked questions
Is Apereo CAS or SimpleSAMLphp better?
Neither is universally better. Apereo CAS has the larger community, while SimpleSAMLphp is simpler to set up (medium difficulty). Choose based on the comparison table above and your own setup.
Are Apereo CAS and SimpleSAMLphp free and open-source?
Yes. Apereo CAS is licensed under Apache-2.0 and SimpleSAMLphp under LGPL-2.1. Both can be self-hosted at no software cost.
Can I run Apereo CAS and SimpleSAMLphp with Docker?
Apereo CAS: yes. SimpleSAMLphp: yes.
Which is lighter on resources, Apereo CAS or SimpleSAMLphp?
SimpleSAMLphp has the smaller minimum footprint at 256 MB of RAM, compared to about 1,024 MB for Apereo CAS. Real-world usage depends on library size, user count, and enabled features.