Keycloak vs Zitadel: which one to choose in 2026?
Both are open source alternatives to Auth0, Okta. We compare license, tech stack and features to help you decide which fits your team best.
| Keycloak | Zitadel | |
|---|---|---|
| Category | Auth & Identity | Auth & Identity |
| License | Apache-2.0 | AGPL-3.0 (con excepciones Apache-2.0/MIT en algunos directorios) |
| GitHub stars | ~36.5k | ~14.9k |
| Tech stack | Java, Quarkus | Go, PostgreSQL |
| Replaces | Auth0, Okta | Auth0, Okta |
Keycloak has more GitHub stars, which usually indicates a larger community (not necessarily that it's the best option for your use case).
Keycloak
Open source SSO and identity management, an alternative to Auth0/Okta.
Pros
- Permissive Apache-2.0 license, with 36k+ GitHub stars and a verified deployment
Things to consider
- Higher memory usage than lighter alternatives
Zitadel
All-in-one multi-tenant identity, an alternative to Auth0/Okta.
Pros
- Built from the ground up for multi-tenant SaaS
Things to consider
- Documentation is thinner than Keycloak's for advanced cases
- AGPL-3.0: a strong copyleft license, with source-sharing obligations for covered modified versions and certain network use, under its terms
Key features
Keycloak
- SSO and LDAP/Active Directory federation
- Social login (Google, GitHub...)
- Granular role and permission management
Zitadel
- Native multi-tenancy (organizations)
- SSO, MFA and per-org project management
- Full gRPC and REST APIs
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