Last winter, a startup building medical imaging analysis software received a security questionnaire from a client. One line asked something simple: “Where is your employee and customer identity authentication data physically stored, and who hosts it?”
The technical lead checked the backend and found the answer: servers belonging to a US-based SaaS identity provider, exact data center location undisclosed, with terms stating the company “may transfer data to any jurisdiction in which we operate.”
That line held up the questionnaire for three full weeks. The client was a European hospital group. Eventually, the startup made a decision: move identity authentication entirely onto their own infrastructure, with zero reliance on a third party for a single line of that code.
This isn’t an isolated story. Once a team starts working with clients in heavily regulated industries like healthcare, finance, or government, or simply doesn’t want to be at the mercy of a vendor’s next price hike, acquisition, or terms change, “run our own identity system” stops being a technical choice and becomes a matter of business survival.
The good news is this path is far more walkable than it was five years ago. The open-source world has grown several self-hosted identity providers (IdP for short, the system responsible for answering “who are you and what can you do”) mature enough to run in production. Today’s subject is Authentik, alongside the three peers it inevitably gets compared to: Authelia, Keycloak, and Zitadel.
First, let’s be clear: these four are not the same category as Okta or Auth0
If you’ve looked into identity solutions before, you’ve probably run into Okta, Auth0, or Clerk. They do similar things: unified login, single sign-on (SSO), multi-factor authentication. But the business model is completely different. Your user data lives on their cloud, you pay per user or per API call, and at bottom you’re outsourcing the concept of “trust” to a third party.
Authentik, Authelia, Keycloak, and Zitadel take a different road. All four are open source, meaning you can audit the code yourself. They run on your own servers or your private cloud, and user data never leaves your infrastructure from creation to deletion. You don’t pay a monthly fee per user, but you do need someone on staff to maintain the system. That’s the price of independence, and it’s a tradeoff plenty of teams weigh carefully before committing to.
Among these four, Keycloak is the elder statesman. Red Hat has backed it for over a decade, it has the deepest enterprise feature set, and it sits underneath the internal identity systems of many large organizations. Zitadel is the newer challenger, built cloud-native from the ground up and particularly friendly to Kubernetes environments. Authelia takes the lightweight route, focused on doing one thing well: adding an authentication layer in front of your existing reverse proxy, like Nginx or Traefik. Authentik tries to strike a balance between full feature coverage and simple deployment, and its interface friendliness is one of the reasons it keeps coming up in conversation.
Starting with a concrete scenario: you just want a login wall for internal tools
Picture a team running a dozen internal tools: a monitoring dashboard, a log viewer, a CI/CD console, scattered across different subdomains. Each tool has its own login logic, and some don’t have any access control at all. Anyone who lands an internal IP address can walk right in. This is the reality for a lot of growing companies.
In this scenario, Authelia is the least stressful answer. It doesn’t try to be a full-blown identity platform. Instead it focuses on being an authentication gateway that sits at the reverse proxy layer: you put it in front of Nginx or Traefik, configure your domain rules, and every request has to pass through it before reaching the backend service. It supports single-factor password login as well as two-factor authentication via TOTP codes. Configuration lives in YAML, which makes it low-friction for teams already comfortable with containerized deployments.
Its limitation is just as clear. If what you actually need is fine-grained, per-application role management, Authelia wasn’t built for that. It behaves more like a purpose-built tool that does one job well rather than a full platform.
When your org chart is complex enough to need departments, roles, and permissions
Now shift to a different scenario. Your company has sales, engineering, finance, and external contractors, each with different access to different systems and different visibility into data, and that permission structure keeps shifting as the org chart evolves.
This is where Keycloak’s enterprise DNA shows up. It supports full role and group management, fine-grained authorization policies, and built-in support for SAML, OpenID Connect, and OAuth2, the main authentication protocols in use today. It can integrate with almost any third-party system that needs single sign-on. In industries like finance and healthcare where compliance audits are strict, Keycloak is a proven choice, backed by an enterprise software vendor with a long track record of maintenance.
The tradeoff is the learning curve. Keycloak’s admin console has enough surface area to disorient a newcomer, and getting your head around core concepts like realms, clients, and roles on your first deployment can eat up real time with the documentation. It suits teams with dedicated staff for long-term upkeep more than it suits a team that just wants to ship a login feature quickly.
If you’re already living in Kubernetes and want native integration that just fits
Here’s a more modern scenario. Your entire infrastructure already runs on Kubernetes, deployments are managed through Helm, and your team thinks in terms of cloud-native declarative configuration. Bringing in a system whose deployment model clashes with that mindset makes the whole architecture feel disjointed.
Zitadel exists for exactly this situation. It was designed from the start with cloud-native and multi-tenant use cases in mind (multi-tenant meaning one system serving multiple independent customers whose data stays isolated from each other). It’s natively friendly to Kubernetes deployment, and both configuration and scaling can be handled the cloud-native way. It supports OpenID Connect and SAML as well, with fine-grained permission management, sitting somewhere between Authelia’s lightness and Keycloak’s heavyweight enterprise footprint.
Teams usually pick Zitadel once they’ve already decided the entire stack should modernize, not simply because they need to solve a login problem. If your team is still running on traditional virtual machines, bringing in Zitadel can feel like grafting on a piece that doesn’t quite match your existing habits.
So what gap does Authentik fill
After looking at the previous three, a pattern probably jumps out: Authelia is light but narrow, Keycloak is comprehensive but complex, and Zitadel is modern but deeply tied to cloud-native infrastructure. Each of the three guards its own territory, and that leaves a gap in the middle for teams that need more coverage than Authelia offers, don’t want to absorb Keycloak’s learning curve, and aren’t necessarily committed to the Kubernetes ecosystem.
Authentik is built to fill that gap. It supports the same major protocols, OAuth2, SAML, and LDAP (an older but still widely used directory protocol inside many enterprise internal systems), with feature coverage that approaches Keycloak’s. But it puts more thought into the admin interface design. Its backend has a visual flow editor, letting you configure every step of login, registration, and password recovery in something closer to a building-block interface rather than piling parameters into a config file. For teams that don’t deal with identity systems every day, that design makes a real difference in approachability.
On the deployment side, Authentik ships an official Docker Compose configuration, and its community keeps growing. When you run into a problem, checking the docs or community discussion usually turns up an existing answer. It doesn’t try to match every corner of Keycloak’s enterprise feature set, but for most small and mid-sized teams who want functionality that’s good enough without getting dragged down by complex configuration, it covers the ground pretty solidly.
Putting all four side by side
After all these scenario stories, when it comes to actually choosing, you probably want something you can scan quickly. Worth saying up front: this table isn’t meant to crown a winner, because these four tools aren’t competing on the same axis. Each one serves a different level of deployment complexity and team size. The table just compresses the scenario differences already covered into something easier to skim.
| Dimension | Authentik | Authelia | Keycloak | Zitadel |
|---|---|---|---|---|
| Positioning | Full-featured, interface-friendly | Lightweight reverse-proxy gateway | Enterprise full-feature platform | Cloud-native multi-tenant solution |
| Deployment complexity | Moderate, official Docker Compose | Low, simple configuration | High, many concepts to learn | Moderate, Kubernetes-friendly |
| Protocol support | OAuth2 / SAML / LDAP | Single and two-factor auth | OAuth2 / SAML / OpenID Connect | OpenID Connect / SAML |
| Permission granularity | Medium-high, visual flow editor | Low, not the core focus | High, full role and group system | High, native multi-tenant design |
| Best fit team size | Small to mid-sized teams | Any size, especially internal tools | Mid-to-large, compliance-heavy orgs | Teams already on cloud-native architecture |
| Maintenance backing | Active open-source community | Active community, narrow focus | Red Hat-backed, long-term support | Commercial-backed open-source project |
| License | MIT | Apache 2.0 | Apache 2.0 | AGPLv3 (some enterprise features commercially licensed) |
When you’re reading this table, the point isn’t to compare rows line by line. Ask yourself one question first: is your pain point closer to “I want a login wall that’s not a pain to maintain,” “I need to support an entire organization’s permission structure,” or “our whole infrastructure is moving cloud-native.” The answer usually points you toward the right corner of the table.
Back to the medical imaging company: what did they end up choosing
That company wasn’t large, just over a dozen people, but their client had strict compliance requirements, and their permission system needed to separate internal staff accounts from external hospital client accounts. They landed on Authentik, for reasons that were pretty straightforward: Keycloak offered more than they needed and cost more to maintain than the team could absorb; Authelia wasn’t enough to support the multi-role permission split they needed; and while Zitadel was modern, their infrastructure hadn’t fully migrated to Kubernetes yet, so its cloud-native advantages didn’t apply to them yet.
Once deployed, that security questionnaire that had been stuck for three weeks finally got a clear answer: identity data stored on servers they controlled, with physical location, access logs, and backup policy all fully documented. The technical lead later mentioned that maintenance turned out cheaper than expected, because Authentik’s visual flow configuration actually lowered the barrier to troubleshooting. They didn’t need to dig through source-level documentation every time something needed adjusting.
Building your own identity system was never a contest to find the “strongest” tool. It’s a practical judgment call about how much complexity your team can actually handle right now. If you’re wrestling with this decision, start by getting clear on your team’s size, your compliance pressure, and your existing infrastructure. The answer tends to be clearer than it looks from the outside.
Related reading
- Self-Hosted Auth for Developers: Better Auth vs Authelia vs Supabase Auth
- Okta vs Auth0 vs Clerk: Identity Providers Compared for 2026
- When You Swap the Model, Is It Still Your Agent?
- Splunk vs Elastic: The Identity Crisis Behind Your Log Management Choice
- AI Recursive Self-Improvement and the Singularity: Where We Stand in 2026
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