head to head · open source
Authentik vs pac4j
Authentik has 25,795 GitHub stars, 2,052 forks, 1,074 open issues and last shipped today. pac4j has 2,530 stars, 711 forks, 5 open issues and last shipped yesterday. Authentik leads on adoption by 920% (25,795 vs 2,530 stars). Authentik is written in Python under a custom or non-standard licence; pac4j is written in Java under Apache-2.0. Authentik has attracted 8% as many forks as stars, pac4j 28%. Authentik was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 4 topic tags (authentication, authorization, oauth2, 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
| Authentik | pac4j | |
|---|---|---|
| GitHub stars | ★ 26K | ★ 2.5K |
| License | Custom / other | Apache-2.0 |
| Written in | Python | Java |
| Last push | 2026-10-01 | 2026-09-30 |
| Forks | ⑂ 2.1K | ⑂ 711 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Authentik if
- You weight community size — 26K stars and counting
- You want the Custom / other license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick pac4j if
- You want the pac4j feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Java
- You evaluated both and pac4j fits your workflow better
About Authentik
Authentik is an open source Identity Provider (IdP) built for modern single sign on (SSO) workflows. It operates in the identity and access management (IAM) ecosystem, offering a self hosted alternative to commercial solutions like Auth0, Okta, and Entra ID. The project is written in Python and distributed under a mixed MIT/CC BY SA/enterprise license model, with a core open source offering and an enterprise tier for advanced features and support.
read the full Authentik overview →
About pac4j
pac4j is a security engine for Java that adds authentication and authorization — across OpenID Connect, SAML 2, CAS, OAuth, JWT, LDAP and more — to any Java framework through one shared API.
read the full pac4j overview →
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Frequently asked questions
Is Authentik or pac4j more popular?
Authentik has 25,795 GitHub stars and pac4j has 2,530. Authentik has the larger community by that measure.
Are Authentik and pac4j free?
Both are open source. Authentik has no licence declared in this registry, and pac4j is licensed under Apache-2.0. Both are free to self-host.
What is the difference between Authentik and pac4j?
Authentik is written in Python and pac4j in Java. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Authentik or pac4j?
Choose Authentik if you want the larger community (25,795 stars) or its Custom / other licence terms. Choose pac4j if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.