FusionAuth vs Gluu Flex
A side-by-side comparison of two self-hosted identity & sso options — licensing, setup difficulty, resource needs, and what each one replaces.
FusionAuth
Complete authentication and authorization platform
VS
Gluu Flex
Enterprise identity and access management platform
| Feature | FusionAuth | Gluu Flex |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 70 · Good | 69 · Good |
| Category | Identity & SSO | Identity & SSO |
| License | Apache-2.0 | Apache-2.0 |
| Language | Dockerfile | TypeScript |
| Setup difficulty | Medium | Hard |
| Min. RAM | 1,024 MB | 4,096 MB |
| Deployment | docker, kubernetes, bare-metal | docker, kubernetes, helm |
| GitHub stars | ★ 241 | ★ 31 |
| First released | 2018 | 2009 |
| Replaces | Auth0, Okta | Okta, Ping Identity |
What are FusionAuth and Gluu Flex?
FusionAuth
FusionAuth is a self-hostable customer identity and access management platform supporting OAuth, OIDC, SAML, MFA, and user management. The community edition runs free on your own infrastructure.
- OAuth, OIDC and SAML support
- Multi-factor authentication
- User and tenant management
- Themable login pages
Gluu Flex
Gluu provides a self-hostable identity platform for single sign-on, multi-factor authentication, and access management built on open standards. It supports OAuth, OIDC, SAML, and FIDO2.
- Single sign-on
- OAuth, OIDC and SAML
- FIDO2 strong authentication
- Kubernetes deployment
FusionAuth vs Gluu Flex: key differences
FusionAuth is written in Dockerfile, while Gluu Flex is built with TypeScript. FusionAuth is the lighter option, starting around 1,024 MB of RAM against 4,096 MB for Gluu Flex. Gluu Flex is the more established project (first released 2009), while FusionAuth arrived in 2018. FusionAuth has the considerably larger community, at 241 GitHub stars versus 31.
Why pick each one
Choose FusionAuth if…
- Released under the Apache-2.0 license
- First-class Docker support for quick deployment
- Kubernetes-ready with Helm charts available
- Written in Dockerfile
Choose Gluu Flex if…
- Released under the Apache-2.0 license
- First-class Docker support for quick deployment
- Kubernetes-ready with Helm charts available
- Written in TypeScript
Frequently asked questions
Is FusionAuth or Gluu Flex better?
FusionAuth is the stronger all-round pick: it has both the larger community and the simpler medium setup. Consider Gluu Flex if its specific feature set fits your needs better.
Are FusionAuth and Gluu Flex free and open-source?
Yes. FusionAuth is licensed under Apache-2.0 and Gluu Flex under Apache-2.0. Both can be self-hosted at no software cost.
Can I run FusionAuth and Gluu Flex with Docker?
FusionAuth: yes. Gluu Flex: yes.
Which is lighter on resources, FusionAuth or Gluu Flex?
FusionAuth has the smaller minimum footprint at 1,024 MB of RAM, compared to about 4,096 MB for Gluu Flex. Real-world usage depends on library size, user count, and enabled features.