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Cloud · head to head

Azure Functions vs Keycloak

Azure Functions logo

Azure Functions

Cloud

Event-driven serverless compute on Azure

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: Azure Functions consumption plan free grant is capped at 1 million executions and 400,000 GB-seconds of resource consumption per month per subscription, billed per GB-second beyond that; 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 Azure Functions and Keycloak actually diverge.

Attributes where Azure Functions and Keycloak differ
AttributeAzure FunctionsKeycloak
Pricing modelusage-basedopen-source
PlatformsWebSelf-hosted, Docker, Kubernetes, Linux, Windows, API
CategoryCloudDeveloper Tools

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

What people use each for

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

Azure Functions

  • Event-driven computingnot Keycloak
  • Serverless application backendnot Keycloak
  • Scalable API endpointsnot Keycloak

Keycloak

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

Where each one falls short

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

Azure Functions

  • Consumption plan free grant is capped at 1 million executions and 400,000 GB-seconds of resource consumption per month per subscription, billed per GB-second beyond that
  • The newer Flex Consumption plan's free grant is smaller still, at 250,000 executions and 100,000 GB-seconds per month
  • Premium plan avoids per-execution charges but bills continuously for allocated core seconds and memory regardless of invocation volume
  • Memory is rounded up to the nearest 128 MB and execution time to the nearest 1 ms for billing, so small overages round upward

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

Azure Functions

Free
  • Consumption Plan$null/month
    • 1 million requests free monthly
    • 400,000 GB-seconds free monthly
    • Billed per second and executions
  • Flex Consumption Plan$null/month
    • 250,000 executions free monthly
    • 100,000 GB-seconds free monthly
    • Event-driven scaling
  • Premium Plan$null/month
    • No execution charges
    • At least one instance required
    • Includes automatic scaling and VNET access

Keycloak

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

Which should you pick?

Choose Azure Functions if

  • You want to start without paying.
Azure Functions 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 Azure Functions or Keycloak better?
Neither clearly leads. Azure Functions 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, Azure Functions or Keycloak?
Azure Functions starts at Free and Keycloak at Free.
Does Azure Functions or Keycloak run on more platforms?
Azure Functions runs on Web. Keycloak runs on Self-hosted, Docker, Kubernetes, Linux, Windows, API.
Can I use Azure Functions for free?
Both have a free tier, so you can try either at no cost before committing.
What is Azure Functions best used for?
Azure Functions is most often used for event-driven computing, serverless application backend, scalable api endpoints. Of those, event-driven computing and serverless application backend are not what Keycloak is typically brought in for.

Answered from the vendors’ own pages

Azure Functions: Does Azure Functions have a free tier?

Yes, Azure Functions includes a monthly free grant of 1 million requests and 400,000 GB-seconds on the Consumption Plan, or 250,000 executions and 100,000 GB-seconds on Flex Consumption.

Source
Keycloak: What protocols does Keycloak support?

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

Source
Azure Functions: What is Azure Functions' pricing model?

Azure Functions uses usage-based pricing. Consumption plans charge per second of resource consumption and per execution, measured in gigabyte-seconds and rounded to the nearest 128 MB.

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
Azure Functions: What is the minimum execution time for Azure Functions?

The minimum execution time is 100 milliseconds on Consumption plans. Premium plans charge based on core seconds and allocated memory.

Source
Keycloak: Is Keycloak free?

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

Source
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