Softwr

Web Development · head to head

HTMX vs Keycloak

HTMX logo

HTMX

Web Development

Lightweight JavaScript library enabling AJAX, WebSockets, and server-sent events in HTML

From
Free
Free plan
Yes
Full reviewWebsite
Keycloak logo

Keycloak

Developer Tools

Open-source identity and access management server.

From
Free
Free plan
Yes
Full reviewWebsite

The short version

  • Each has a real cost: HTMX best suited for server-rendered architectures, not pure client-side SPAs; Keycloak requires self-hosted deployment and operational expertise to install, configure and maintain
  • Prices and features above were last checked on 29 August 2026.

Where they differ

Only the attributes on which HTMX and Keycloak actually diverge.

Attributes where HTMX and Keycloak differ
AttributeHTMXKeycloak
PlatformsWebSelf-hosted, Docker, Kubernetes, Linux, Windows, API
CategoryWeb DevelopmentDeveloper Tools

Identical on both: starting price (Free), pricing model (open-source), free tier (Yes), user rating (Not yet rated).

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 HTMX

  • AJAX requests
  • HTTP verb support
  • DOM targeting
  • Swap strategies
  • WebSocket support
  • Server-sent events
  • Out-of-band updates

Only in Keycloak

Nothing recorded that HTMX does not also cover.

What people use each for

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

HTMX

  • Building interactive applications without JavaScript framework complexitynot Keycloak
  • Server-rendered applications requiring dynamic updatesnot Keycloak
  • Adding interactivity to existing server-side applicationsnot Keycloak
  • Hypermedia-driven applications using HTML-first approachesnot Keycloak

Keycloak

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

Where each one falls short

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

HTMX

  • Best suited for server-rendered architectures, not pure client-side SPAs
  • Limited client-side state management capabilities compared to frameworks
  • Smaller ecosystem with fewer third-party libraries and tools
  • Learning curve for developers from JavaScript framework backgrounds

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

Pricing, plan by plan

HTMX

Free

No published plan breakdown. See the HTMX review.

Keycloak

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

Which should you pick?

Choose HTMX if

  • You need ajax requests.
  • You want to start without paying.
  • You also want http verb support.
HTMX review

Choose Keycloak if

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

Questions people ask

Is HTMX or Keycloak better?
Neither clearly leads. HTMX starts at Free and Keycloak at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, HTMX or Keycloak?
HTMX starts at Free and Keycloak at Free.
Does HTMX or Keycloak run on more platforms?
HTMX runs on Web. Keycloak runs on Self-hosted, Docker, Kubernetes, Linux, Windows, API.
Can I use HTMX for free?
Both have a free tier, so you can try either at no cost before committing.
What is HTMX best used for?
HTMX is most often used for building interactive applications without javascript framework complexity, server-rendered applications requiring dynamic updates, adding interactivity to existing server-side applications, hypermedia-driven applications using html-first approaches. Of those, building interactive applications without javascript framework complexity and server-rendered applications requiring dynamic updates are not what Keycloak is typically brought in for.
What can HTMX do that Keycloak cannot?
HTMX covers AJAX requests, HTTP verb support, DOM targeting, Swap strategies.

Answered from the vendors’ own pages

HTMX: How big is the HTMX JavaScript library?

HTMX is only 16 kilobytes minified and gzipped with zero external dependencies.

Source
Keycloak: What protocols does Keycloak support?

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

Source
HTMX: Can HTMX work with JSON APIs?

While HTMX is optimized for HTML responses, it can work with JSON through additional configuration and response handling.

Source
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
HTMX: Does HTMX support real-time features like WebSockets?

Yes, HTMX includes support for WebSockets and server-sent events for real-time bidirectional communication.

Source
Keycloak: Is Keycloak free?

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

Source
Share

Related pages

More on HTMX

More on Keycloak

Keep looking

Other head to heads