head to head · open source
Keycloak vs hydra
Keycloak has 37,657 GitHub stars, 9,129 forks, 3,292 open issues and last shipped yesterday. hydra has 17,646 stars, 1,620 forks, 98 open issues and last shipped 3 months ago. Keycloak leads on adoption by 113% (37,657 vs 17,646 stars). Keycloak is written in Java under Apache-2.0; hydra is written in Go under Apache-2.0. Keycloak has attracted 24% as many forks as stars, hydra 9%. Keycloak was the more recently maintained of the two, and both are self-hostable with no licence fee.
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 | hydra | |
|---|---|---|
| GitHub stars | ★ 38K | ★ 18K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Java | Go |
| Last push | 2026-11-02 | 2026-07-29 |
| Forks | ⑂ 9.1K | ⑂ 1.6K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Keycloak if
- You weight community size — 38K 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 hydra if
- You want the hydra feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Go
- You evaluated both and hydra fits your workflow better
About Keycloak
Open Source Identity and Access Management Add authentication to applications and secure services with minimum effort. No need to deal with storing users or authenticating users. Keycloak provides user federation, strong authentication, user management, fine grained authorization, and more. Help and Documentation Documentation User Mailing List Mailing list for help and general questions about Keycloak Join keycloak for general questions, or keycloak dev on Slack for design and development discussions, by creating an account at Reporting Security Vulnerabilities If you have found a security vulnerability, please…
read the full Keycloak overview →
About hydra
Chat · Discussions · Newsletter · Docs · Try Ory Network · Jobs Ory Hydra is a hardened, OpenID Certified OAuth 2.0 Server and OpenID Connect Provider optimized for low latency, high throughput, and low resource consumption. It connects to your existing identity provider through a login and consent app, giving you absolute control over the user interface and experience. What is Ory Hydra? Why Ory Hydra OAuth2 and OpenID Connect: Open Standards OpenID Connect Certified Deployment options Use Ory Hydra on the Ory Network Self host Ory Hydra Quickstart Who is using Ory Hydra Ecosystem Ory Kratos: Identity and User…
read the full hydra overview →
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Frequently asked questions
Is Keycloak or hydra more popular?
Keycloak has 37,657 GitHub stars and hydra has 17,646. Keycloak has the larger community by that measure.
Are Keycloak and hydra free?
Both are open source. Keycloak is licensed under Apache-2.0 and hydra under Apache-2.0. Neither carries a licence fee.
What is the difference between Keycloak and hydra?
Keycloak is written in Java and hydra 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 hydra?
Choose Keycloak if you want the larger community (37,657 stars) or its Apache-2.0 licence terms. Choose hydra if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.