Keycloak vs SimpleSAMLphp
A side-by-side comparison of two self-hosted identity & sso options — licensing, setup difficulty, resource needs, and what each one replaces.
Keycloak
Open-source identity and access management for modern apps
VS
SimpleSAMLphp
PHP implementation of SAML and identity federation
| Feature | Keycloak | SimpleSAMLphp |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 99 · 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 | ★ 36,967 | ★ 1,142 |
| First released | 2014 | 2007 |
| Replaces | Okta, Auth0, Microsoft Entra ID | Okta, PingFederate |
What are Keycloak and SimpleSAMLphp?
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
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
Keycloak vs SimpleSAMLphp: key differences
Keycloak is written in Java, while SimpleSAMLphp is built with PHP. Licensing differs — Apache-2.0 for Keycloak versus LGPL-2.1 for SimpleSAMLphp. SimpleSAMLphp is the lighter option, starting around 256 MB of RAM against 1,024 MB for Keycloak. SimpleSAMLphp is the more established project (first released 2007), while Keycloak arrived in 2014. Keycloak has the considerably larger community, at 36,967 GitHub stars versus 1,142.
Why pick each one
Choose Keycloak if…
- Mature and battle-tested
- Strong enterprise feature set
Watch out for
- Steep learning curve
- Resource intensive
Choose SimpleSAMLphp if…
- Proven and widely deployed
- Flexible modules
Watch out for
- Configuration is intricate
- PHP performance limits
Frequently asked questions
Is Keycloak or SimpleSAMLphp better?
Neither is universally better. Keycloak 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 Keycloak and SimpleSAMLphp free and open-source?
Yes. Keycloak is licensed under Apache-2.0 and SimpleSAMLphp under LGPL-2.1. Both can be self-hosted at no software cost.
Can I run Keycloak and SimpleSAMLphp with Docker?
Keycloak: yes. SimpleSAMLphp: yes.
Which is lighter on resources, Keycloak or SimpleSAMLphp?
SimpleSAMLphp has the smaller minimum footprint at 256 MB of RAM, compared to about 1,024 MB for Keycloak. Real-world usage depends on library size, user count, and enabled features.