Apereo CAS vs Ory Kratos
A side-by-side comparison of two self-hosted identity & sso options — licensing, setup difficulty, resource needs, and what each one replaces.
Not the right match-up?
Apereo CAS
Enterprise single sign-on server for web applications
VS
Ory Kratos
Headless identity and user management API server
| Feature | Apereo CAS | Ory Kratos |
|---|---|---|
| Category | Identity & SSO | Identity & SSO |
| License | Apache-2.0 | Apache-2.0 |
| Language | Java | Go |
| Setup difficulty | Hard | Hard |
| Min. RAM | 1,024 MB | 256 MB |
| Deployment | docker, kubernetes, bare-metal | docker, kubernetes, binary |
| GitHub stars | ★ 11,354 | ★ 13,815 |
| First released | 2004 | 2020 |
| Replaces | Okta, Ping Identity | Auth0, Firebase Auth |
Why pick each one
Choose Apereo CAS if…
- Mature SSO with broad protocol support
- Widely adopted in academia
Choose Ory Kratos if…
- Extremely flexible architecture
- Excellent for custom frontends
Frequently asked questions
Is Apereo CAS or Ory Kratos better?
Neither is universally better. Ory Kratos has the larger community; both share a hard setup difficulty, so the decision comes down to features and licensing.
Are Apereo CAS and Ory Kratos free and open-source?
Yes. Apereo CAS is licensed under Apache-2.0 and Ory Kratos under Apache-2.0. Both can be self-hosted at no software cost.
Can I run Apereo CAS and Ory Kratos with Docker?
Apereo CAS: yes. Ory Kratos: yes.