head to head · open source
Keycloak vs Zitadel
Keycloak has 36,832 GitHub stars, 8,941 forks, 3,292 open issues and last shipped yesterday. Zitadel has 15,041 stars, 1,309 forks, 1,171 open issues and last shipped yesterday. Keycloak leads on adoption by 145% (36,832 vs 15,041 stars). Keycloak is written in Java under Apache-2.0; Zitadel is written in Go under AGPL-3.0. Keycloak has attracted 24% as many forks as stars, Zitadel 9%. Zitadel was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (oidc), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| Keycloak | Zitadel | |
|---|---|---|
| GitHub stars | ★ 37K | ★ 15K |
| License | Apache-2.0 | AGPL-3.0 |
| Written in | Java | Go |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 8.9K | ⑂ 1.3K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Keycloak if
- You weight community size — 37K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Java
- You value the larger contributor base for long-term maintenance
pick Zitadel if
- You want the Zitadel feature set and don't need the biggest community
- You prefer the AGPL-3.0 license terms
- Your stack matches Go
- You evaluated both and Zitadel fits your workflow better
About Keycloak
Keycloak is an open source identity and access management server, written in Java and licensed under Apache 2.0, that adds authentication and access control to applications and services, and it is intended for teams and organisations that want to own their user store rather than rent one.
read the full Keycloak overview →
About Zitadel
Zitadel is an open source identity and access management platform written in Go and released under the AGPL 3.0 license. It lives in the open source IAM ecosystem and provides identity infrastructure for developers who need to operate an authentication and authorization layer themselves.
read the full Zitadel overview →
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Frequently asked questions
Is Keycloak or Zitadel more popular?
Keycloak has 36,832 GitHub stars and Zitadel has 15,041. Keycloak has the larger community by that measure.
Are Keycloak and Zitadel free?
Both are open source. Keycloak is licensed under Apache-2.0 and Zitadel under AGPL-3.0. Neither carries a licence fee.
What is the difference between Keycloak and Zitadel?
Keycloak is written in Java and Zitadel in Go. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Keycloak or Zitadel?
Choose Keycloak if you want the larger community (36,832 stars) or its Apache-2.0 licence terms. Choose Zitadel if its feature set, stack or AGPL-3.0 licence fits better. Both are self-hostable.