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Developer Tools · head to head

Keycloak vs Swagger UI

Keycloak logo

Keycloak

Developer Tools

Open-source identity and access management server.

From
Free
Rated
-
Full reviewWebsite
Swagger UI logo

Swagger UI

Developer Tools

Interactive API documentation generated from OpenAPI specs

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Keycloak requires self-hosted deployment and operational expertise to install, configure and maintain; Swagger UI only as good as the specification: a thin OpenAPI file produces thin documentation

Where they differ

Only the attributes on which Keycloak and Swagger UI actually diverge.

Attributes where Keycloak and Swagger UI differ
AttributeKeycloakSwagger UI
Pricing modelopen-sourceOpen source, no licence fee
PlatformsSelf-hosted, Docker, Kubernetes, Linux, Windows, APIWeb, Self-hosted, Docker

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Developer Tools).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Keycloak

Nothing recorded that Swagger UI does not also cover.

Only in Swagger UI

  • OpenAPI rendering
  • Try it out
  • Schema display
  • Self-hostable

What people use each for

The jobs each tool is most often brought in to do.

Keycloak

  • Organisations requiring self-hosted identity infrastructure for compliance or data residencynot Swagger UI
  • Companies with existing LDAP/Active Directory systems needing federated authenticationnot Swagger UI
  • Open-source projects and communities requiring free IAM without licensing costsnot Swagger UI
  • Enterprises building custom identity workflows requiring fine-grained authorisationnot Swagger UI
  • Teams with sufficient operational expertise to manage infrastructurenot Swagger UI

Swagger UI

  • Publishing API documentation that stays in step with the specificationnot Keycloak
  • Letting developers try endpoints before writing any client codenot Keycloak
  • Internal API discovery across teamsnot Keycloak

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Keycloak

  • Requires self-hosted deployment and operational expertise to install, configure and maintain
  • No managed cloud option provided by Red Hat; organisations must operate infrastructure themselves or use third-party distributions
  • Clustering and high-availability configurations require additional operational knowledge
  • Community support only; commercial support requires third-party vendors or distributions

Swagger UI

  • Only as good as the specification: a thin OpenAPI file produces thin documentation
  • Default presentation is dated compared with modern documentation tools
  • Large specifications render slowly and become hard to navigate
  • Try it out against production needs care with authentication and CORS, and is often disabled as a result

Pricing, plan by plan

Keycloak

Free
  • Open-sourceFree
    • Full platform functionality
    • Self-hosted deployment
    • Community support

Swagger UI

Free
  • Swagger UIFree
    • Full functionality
    • Commercial use permitted
    • Community support

Which should you pick?

Choose Keycloak if

  • You want to start without paying.
  • You work on Self-hosted, Docker, Kubernetes, Linux, Windows, API.
Keycloak review

Choose Swagger UI if

  • You need openapi rendering.
  • You want to start without paying.
  • You work on Web, Self-hosted, Docker.
  • You also want try it out.
Swagger UI review

Questions people ask

Is Keycloak or Swagger UI better?
Neither clearly leads. Keycloak starts at Free and Swagger UI at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Keycloak or Swagger UI?
Keycloak starts at Free and Swagger UI at Free.
Does Keycloak or Swagger UI run on more platforms?
Keycloak runs on Self-hosted, Docker, Kubernetes, Linux, Windows, API. Swagger UI runs on Web, Self-hosted, Docker.
Can I use Keycloak for free?
Both have a free tier, so you can try either at no cost before committing.
What is Keycloak best used for?
Keycloak is most often used for organisations requiring self-hosted identity infrastructure for compliance or data residency, companies with existing ldap/active directory systems needing federated authentication, open-source projects and communities requiring free iam without licensing costs, enterprises building custom identity workflows requiring fine-grained authorisation. Of those, organisations requiring self-hosted identity infrastructure for compliance or data residency and companies with existing ldap/active directory systems needing federated authentication are not what Swagger UI is typically brought in for.
What can Keycloak do that Swagger UI cannot?
Swagger UI covers OpenAPI rendering, Try it out, Schema display, Self-hostable.

Answered from the vendors’ own pages

Keycloak: What protocols does Keycloak support?

Keycloak supports OpenID Connect, OAuth 2.0 and SAML 2.0 protocols for authentication and authorisation.

Source
Swagger UI: Is Swagger UI free?

Yes, open source under the Apache 2.0 licence. SmartBear sells commercial SwaggerHub separately.

Keycloak: Can Keycloak integrate with existing user directories?

Yes. Keycloak supports user federation with LDAP and Active Directory systems, allowing organisations to leverage existing user directories.

Source
Swagger UI: What is the difference between Swagger and OpenAPI?

OpenAPI is the specification format; Swagger is the toolset around it, including Swagger UI. The specification was renamed from Swagger to OpenAPI in 2016.

Keycloak: Is Keycloak free?

Yes. Keycloak is fully open-source and free to deploy and use. No licensing fees are required.

Source
Swagger UI: Can Swagger UI make real API calls?

Yes, through its try-it-out control, though authentication and CORS configuration often mean it is disabled for production APIs.

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