Auth0 is a popular platform when it comes to identity and access management services. However, the growing need for customizable, self-hosted solutions has led many organizations to explore open-source alternatives.

In this article, we will look at six solid open-source alternatives to Auth0 that provide similar functionality while giving you the benefits of a self-hosted and community-driven identity infrastructure.

Selection criteria

There are a few factors we took into account when selecting these alternatives. Yes, we want solutions that provide authentication solutions, but we also considered the following criteria for selecting them:

• Authentication methods: Can they handle things like passwords, social logins, and multi-factor authentication (MFA)?
• Integration options: Do they support common identity protocols like OAuth 2.0, OpenID Connect, or SAML? Can they connect to LDAP or talk to RADIUS for older systems?
• Ease of setup and scaling: How easy is it to run in Docker or Kubernetes? Will it scale if you have a lot of users?
• Support and community: Is there paid support if you need it, or a strong community with good documentation?

That being said, the top 6 alternatives found based on these criteria are: Keycloak, Gluu, Authentik, Authelia, Supertokens, and FusionAuth.

Overview of alternatives

Lets take a look at each of them and what they can do!

Keycloak

Keycloak is one of the most popular open-source identity solutions. It was created by Red Hat, so you can be confident it’s backed by a big open-source name. It’s known for handling a lot of use cases, you can start small but it also has the depth you need as you grow.

Authentication Details: Keycloak gives you single sign-on (SSO) right out of the box, so users log in once and can access multiple apps. It supports multi-factor methods like time-based one-time passwords (TOTP) or hardware keys (YubiKey, for instance). For social logins, it comes with built-in connectors for Google, GitHub, and more. You can also set up password rules so users pick stronger passwords.

Integrations: Keycloak works with OAuth 2.0, OpenID Connect, and SAML. It can connect directly to LDAP or Active Directory, which is particularly helpful if you have an existing user directory. RADIUS isn’t built in, but you can find plugins made by the community. You can also extend Keycloak with custom code if need be.

Setup and Scaling: Keycloak offers flexible deployment options through Docker and Kubernetes, making it straightforward to get started. You can use standard databases like PostgreSQL or MySQL for storing user and session data. Because it’s been around a while, there are many guides and examples to help with scaling as your user base grows.

Support: You get a big community, active forums, and detailed documentation for free. If you need more, Red Hat offers paid support options so you can get expert help whenever you need it.

Gluu

Gluu aims to be a full toolkit for managing logins and user data. It’s used by places like universities and enterprises that need something solid and dependable.

Authentication Details: Gluu is strong on MFA, offering TOTP, SMS-based codes, and even ways to integrate with biometric checks if you have those. It supports a range of social logins. It also has a handy self-service setup so users can reset their passwords without bugging your IT team.

Integrations: Gluu supports OAuth 2.0, OpenID Connect, UMA (User-Managed Access), and can work with SCIM for provisioning (creating and removing user accounts in bulk). It also ties in nicely with LDAP, Active Directory, and even RADIUS. This makes Gluu a good fit if you have older systems that need to talk to your new login setup.

Setup and Scaling: You can run Gluu in Docker and Kubernetes, and it can store user data in LDAP or SQL databases. Because it’s designed for bigger groups, Gluu has a lot of docs and guides to help you scale smoothly.

Support: Gluu has an enterprise edition and paid support plans. This means if you need direct help or want some custom features, they can work with you.

Authentik

Authentik is a newer player focused on being modern, flexible, and easy to adapt. It’s a good pick if you like to tweak login flows or add new sign-in options without a lot of hassle.

Authentication Details: You can set up MFA with TOTP or hardware keys. Authentik’s “adaptive” MFA means you can choose when to require extra steps based on things like the user’s device. It also supports social logins and can connect to other identity providers. Password policies are customizable, so you can require a certain length or complexity.

Integrations: Authentik supports OAuth 2.0, OIDC, and SAML. It hooks into LDAP easily, letting you use your existing users without moving them. While RADIUS isn't built in, you can implement it through third-party proxies like FreeRADIUS that bridge to LDAP.

Setup and Scaling: It’s built with containers in mind, so you can run Authentik with Docker or Kubernetes. It runs on PostgreSQL as its only supported database. The documentation gives you steps for scaling and caching if you have a bigger user load.

Support: Mainly community support and documentation. Authentik doesn’t have an official paid plan right now, but there are companies that offer consulting if you need more help.

Authelia

Authelia is known for keeping things simple. It’s great if you already have a reverse proxy (like Nginx or Traefik) and you just want to add secure sign-ins to your internal services. It doesn’t try to do everything, it just focuses on the login part.

Authentication Details: You can use MFA with TOTP codes or hardware keys. Passwords are hashed securely. While Authelia doesn't have many built-in social login options, you can add any standard OIDC provider as an authentication source.

Integrations: It’s centered around OAuth 2.0 and OIDC. Authelia can connect to LDAP or Active Directory so you can use your existing user database. Authelia doesn't natively support custom authentication backends.

Setup and Scaling: Authelia is usually run as a single container or binary, making it easy for smaller setups or home labs. It stores sessions in Redis and user data in YAML files or external user stores. For larger setups, you might need to plan a bit, but it’s still simpler than some of the bigger platforms.

Support: No official paid support. You have community docs, GitHub issues, and forums. For more complex needs, you’d have to rely on community or hire outside help.

SuperTokens

SuperTokens is all about simplicity for developers. It offers SDKs for many popular frontend and backend frameworks, making it easy to add sign-in logic without starting from scratch.

Authentication Details: It supports classic email-and-password logins, passwordless options (like magic links), and MFA through TOTP. Social logins are pretty straightforward with well-known providers like Google or GitHub. You also get pre-built functions for handling password resets.

Integrations: SuperTokens works with OAuth 2.0 and OIDC. It doesn’t have native LDAP integration, but if you really need that, you might be able to code something custom. RADIUS isn’t supported.

Setup and Scaling: It runs in Docker, and you can use PostgreSQL or other databases to store user info and sessions. Scaling typically involves adding more instances and a load balancer. Their docs are developer-friendly, showing you how to integrate with frameworks like Node.js, React, and more.

Support SuperTokens offers paid hosting and support plans. If you just want the open-source parts, you can rely on the community. If you’d like someone else to manage it or want faster help, you can pay for their managed services.

FusionAuth

FusionAuth tries to combine ease of use with enough features for bigger teams. It has a free community edition and also an enterprise edition for when you need more help and certain advanced features.

Authentication Details: It supports username/password logins, MFA with TOTP or SMS codes, and WebAuthn for hardware keys. Social logins are built in, and you can add new ones fairly easily. Password rules can be set to ensure users pick secure passwords.

Integrations: FusionAuth works with OAuth 2.0, OIDC, and SAML, making it flexible in mixed environments. It can connect to LDAP directories by using their connectors. RADIUS isn’t built in, but some folks have added it through third-party tools.

Setup and Scaling: You can run FusionAuth as a container and scale it with Kubernetes. It supports using different databases (like PostgreSQL or MySQL). The documentation also covers how to run multiple instances so its always available even if you have a large user base.

Support: They have a paid enterprise edition and also offer professional support. If you just use the community version, you rely on docs and forums, but if you pay, you get direct help and possibly some extra features.

Feature comparison

Conclusion

Each of these open-source alternatives to Auth0 offers unique strengths:

• Keycloak: Best for enterprise-level deployments requiring a comprehensive feature set.
• Gluu: Ideal for organizations needing advanced IAM capabilities and extensive customization.
• Authentik: Great for those seeking a modern, flexible identity solution with strong customization options.
• Authelia: Perfect for projects requiring a lightweight, easy-to-deploy authentication solution.
• SuperTokens: Excellent for developers looking for an easily customizable, self-hosted authentication system.
• FusionAuth: A balanced platform with a nice admin UI and a wide feature set. Easy to scale, and you can pay for enterprise support if you need it.

All of these give you control over your own login system, without handing everything off to a third-party vendor. That way, you get to own your data, shape your login flow, and scale at your own pace.