SimpleSAMLphp vs ZITADEL
A side-by-side comparison of two self-hosted identity & sso options — licensing, setup difficulty, resource needs, and what each one replaces.
ZITADEL
Cloud-native identity infrastructure with multi-tenancy built
| Feature | SimpleSAMLphp | ZITADEL |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 83 · Excellent | 95 · Excellent |
| Category | Identity & SSO | Identity & SSO |
| License | LGPL-2.1 | Apache-2.0 |
| Language | PHP | Go |
| Setup difficulty | Medium | Medium |
| Min. RAM | 256 MB | 512 MB |
| Deployment | bare-metal, source, docker | docker, kubernetes, binary |
| GitHub stars | ★ 1,142 | ★ 15,083 |
| First released | 2007 | 2020 |
| Replaces | Okta, PingFederate | Auth0, Okta, Firebase Auth |
What are SimpleSAMLphp and ZITADEL?
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
ZITADEL
ZITADEL is an open-source identity and access management platform built for multi-tenant applications. It offers OpenID Connect, OAuth2, SAML, passwordless login and a powerful management API.
- Multi-tenancy as a first-class concept
- Passwordless and FIDO2 authentication
- Event-sourced audit trail
- Comprehensive gRPC and REST APIs
SimpleSAMLphp vs ZITADEL: key differences
SimpleSAMLphp is written in PHP, while ZITADEL is built with Go. Licensing differs — LGPL-2.1 for SimpleSAMLphp versus Apache-2.0 for ZITADEL. SimpleSAMLphp is the lighter option, starting around 256 MB of RAM against 512 MB for ZITADEL. SimpleSAMLphp is the more established project (first released 2007), while ZITADEL arrived in 2020. ZITADEL has the considerably larger community, at 15,083 GitHub stars versus 1,142.
Why pick each one
Choose SimpleSAMLphp if…
- Proven and widely deployed
- Flexible modules
Watch out for
- Configuration is intricate
- PHP performance limits
Choose ZITADEL if…
- Strong multi-tenant model
- Modern Go codebase
Watch out for
- Smaller community than Keycloak
Frequently asked questions
Is SimpleSAMLphp or ZITADEL better?
Neither is universally better. ZITADEL has the larger community; both share a medium setup difficulty, so the decision comes down to features and licensing.
Are SimpleSAMLphp and ZITADEL free and open-source?
Yes. SimpleSAMLphp is licensed under LGPL-2.1 and ZITADEL under Apache-2.0. Both can be self-hosted at no software cost.
Can I run SimpleSAMLphp and ZITADEL with Docker?
SimpleSAMLphp: yes. ZITADEL: yes.
Which is lighter on resources, SimpleSAMLphp or ZITADEL?
SimpleSAMLphp has the smaller minimum footprint at 256 MB of RAM, compared to about 512 MB for ZITADEL. Real-world usage depends on library size, user count, and enabled features.