head to head · open source
Keycloak vs oauth2-client
Keycloak has 36,920 GitHub stars, 8,950 forks, 3,292 open issues and last shipped today. oauth2-client has 3,819 stars, 770 forks, 64 open issues and last shipped 6 days ago. Keycloak leads on adoption by 867% (36,920 vs 3,819 stars). Keycloak is written in Java under Apache-2.0; oauth2-client is written in PHP under MIT. Keycloak has attracted 24% as many forks as stars, oauth2-client 20%. 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.
← all 20902 open source comparisons
Side by side
| Keycloak | oauth2-client | |
|---|---|---|
| GitHub stars | ★ 37K | ★ 3.8K |
| License | Apache-2.0 | MIT |
| Written in | Java | PHP |
| Last push | 2026-09-22 | 2026-09-16 |
| Forks | ⑂ 8.9K | ⑂ 770 |
| 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 oauth2-client if
- You want the oauth2-client feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches PHP
- You evaluated both and oauth2-client 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 oauth2-client
league/oauth2 client is an MIT licensed PHP library maintained by The PHP League that provides a reusable base for integrating applications with any OAuth 2.0 service provider, aimed at PHP developers who need to add "Connect with Facebook/Google" style login and token flows without implementing RFC 6749 from scratch.
read the full oauth2-client overview →
More in Security & Privacy
Related comparisons
More Identity & Access Management (IAM) projects
Compare either of these against the rest of the Identity & Access Management (IAM) field.
Frequently asked questions
Is Keycloak or oauth2-client more popular?
Keycloak has 36,920 GitHub stars and oauth2-client has 3,819. Keycloak has the larger community by that measure.
Are Keycloak and oauth2-client free?
Both are open source. Keycloak is licensed under Apache-2.0 and oauth2-client under MIT. Neither carries a licence fee.
What is the difference between Keycloak and oauth2-client?
Keycloak is written in Java and oauth2-client in PHP. 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 oauth2-client?
Choose Keycloak if you want the larger community (36,920 stars) or its Apache-2.0 licence terms. Choose oauth2-client if its feature set, stack or MIT licence fits better. Both are self-hostable.