Keycloak 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.
Keycloak
Open-source identity and access management for modern apps
VS
Ory Kratos
Headless identity and user management API server
| Feature | Keycloak | Ory Kratos |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 99 · Excellent | 89 · Excellent |
| 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 | ★ 36,967 | ★ 13,888 |
| First released | 2014 | 2020 |
| Replaces | Okta, Auth0, Microsoft Entra ID | Auth0, Firebase Auth |
What are Keycloak and Ory Kratos?
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
Ory Kratos
Ory Kratos is an API-first identity and user management system. It handles login, registration, profile management, account recovery and multi-factor authentication without prescribing a user interface.
- Headless API for full UI control
- Self-service flows for login and recovery
- Pluggable MFA including TOTP and WebAuthn
- Cloud-native and stateless design
Keycloak vs Ory Kratos: key differences
Keycloak is written in Java, while Ory Kratos is built with Go. Ory Kratos is the lighter option, starting around 256 MB of RAM against 1,024 MB for Keycloak. Keycloak is the more established project (first released 2014), while Ory Kratos arrived in 2020. Keycloak has the considerably larger community, at 36,967 GitHub stars versus 13,888.
Why pick each one
Choose Keycloak if…
- Mature and battle-tested
- Strong enterprise feature set
Watch out for
- Steep learning curve
- Resource intensive
Choose Ory Kratos if…
- Extremely flexible architecture
- Excellent for custom frontends
Watch out for
- Requires building your own UI
- Complex initial setup
Frequently asked questions
Is Keycloak or Ory Kratos better?
Neither is universally better. Keycloak has the larger community; both share a hard setup difficulty, so the decision comes down to features and licensing.
Are Keycloak and Ory Kratos free and open-source?
Yes. Keycloak 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 Keycloak and Ory Kratos with Docker?
Keycloak: yes. Ory Kratos: yes.
Which is lighter on resources, Keycloak or Ory Kratos?
Ory Kratos 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.