head to head · open source
hydra vs Zitadel
hydra has 17,553 GitHub stars, 1,609 forks, 98 open issues and last shipped 2 months ago. Zitadel has 15,060 stars, 1,317 forks, 1,171 open issues and last shipped 2 days ago. hydra leads on adoption by 17% (17,553 vs 15,060 stars). hydra is written in Go under Apache-2.0; Zitadel is written in Go under AGPL-3.0. hydra has attracted 9% 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 3 topic tags (authorization, identity, oauth2), 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
| hydra | Zitadel | |
|---|---|---|
| GitHub stars | ★ 18K | ★ 15K |
| License | Apache-2.0 | AGPL-3.0 |
| Written in | Go | Go |
| Last push | 2026-07-29 | 2026-09-18 |
| Forks | ⑂ 1.6K | ⑂ 1.3K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick hydra if
- You weight community size — 18K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Go
- 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 hydra
Ory Hydra is an OpenID Certified OpenID Connect and OAuth 2.1 provider written in Go and licensed under Apache 2.0, built for teams that need standards compliant token issuance, client management, and consent flows while user accounts stay in their own existing identity system.
read the full hydra 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 hydra or Zitadel more popular?
hydra has 17,553 GitHub stars and Zitadel has 15,060. hydra has the larger community by that measure.
Are hydra and Zitadel free?
Both are open source. hydra is licensed under Apache-2.0 and Zitadel under AGPL-3.0. Neither carries a licence fee.
What is the difference between hydra and Zitadel?
hydra is written in Go 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, hydra or Zitadel?
Choose hydra if you want the larger community (17,553 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.