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Developer Tools · head to head

Keycloak vs Restate

Keycloak logo

Keycloak

Developer Tools

Open-source identity and access management server.

From
Free
Rated
-
Full reviewWebsite
Restate logo

Restate

Developer Tools

Durable execution engine in Rust with a free tier and low-latency workflows

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; Restate the runtime is under a Business Source Licence rather than an open source licence, so building a competing managed offering on it is prohibited and some procurement functions will reject it on licence grounds alone.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Keycloak and Restate actually diverge.

Attributes where Keycloak and Restate differ
AttributeKeycloakRestate
Pricing modelopen-sourcePer month by durable action count
PlatformsSelf-hosted, Docker, Kubernetes, Linux, Windows, APILinux, macOS, Web

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 Restate does not also cover.

Only in Restate

  • Durable execution
  • Virtual objects
  • Single binary runtime
  • Multi-language SDKs
  • Workflows and sagas
  • Restate Cloud

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 Restate
  • Companies with existing LDAP/Active Directory systems needing federated authenticationnot Restate
  • Open-source projects and communities requiring free IAM without licensing costsnot Restate
  • Enterprises building custom identity workflows requiring fine-grained authorisationnot Restate
  • Teams with sufficient operational expertise to manage infrastructurenot Restate

Restate

  • Payment or order flows where a crash between two external API calls must not double-charge or lose the ordernot Keycloak
  • AI agent loops that call tools over minutes or hours and must survive a deployment mid-runnot Keycloak
  • Replacing hand-rolled retry, idempotency key and outbox code across a set of microservicesnot Keycloak
  • A small team that wants durable workflows without operating a Temporal cluster and its databasenot 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

Restate

  • The runtime is under a Business Source Licence rather than an open source licence, so building a competing managed offering on it is prohibited and some procurement functions will reject it on licence grounds alone.
  • Restate Cloud jumps from a free fifty thousand actions straight to 300 US dollars a month for twenty million, so a workload sitting at a few hundred thousand actions pays enterprise-shaped money for hobby-shaped volume.
  • It is a young project against Temporal’s established base, so hiring engineers who already know it is unrealistic and the answer to most questions is in the docs rather than on Stack Overflow.
  • The programming model requires structuring code around durable handlers and virtual objects, which is a genuine rewrite for existing services rather than a library you add.
  • The single-binary simplicity that makes small deployments cheap also means fewer operational knobs at very large scale than a system designed as separable components.

Pricing, plan by plan

Keycloak

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

Restate

Free
  • FreeFree
    • Fifty thousand durable actions per month
    • No credit card required
    • Community support
  • Starter$300/month
    • Twenty million actions per month
    • Two hundred actions per second, bursting to one thousand
    • Twenty GB storage
  • Pro$1000/month
    • Fifty million actions per month
    • Five hundred actions per second, bursting to two thousand
    • Fifty GB storage
  • Enterprise$undefined/year
    • Negotiated volume
    • Twenty-four seven P0 support
    • 99.99 per cent SLA

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 Restate if

  • You need durable execution.
  • You want to start without paying.
  • You work on Linux, macOS, Web.
  • You also want virtual objects.
Restate review

Questions people ask

Is Keycloak or Restate better?
Neither clearly leads. Keycloak starts at Free and Restate at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Keycloak or Restate?
Keycloak starts at Free and Restate at Free.
Does Keycloak or Restate run on more platforms?
Keycloak runs on Self-hosted, Docker, Kubernetes, Linux, Windows, API. Restate runs on Linux, macOS, Web.
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 Restate is typically brought in for.
What can Keycloak do that Restate cannot?
Restate covers Durable execution, Virtual objects, Single binary runtime, Multi-language SDKs.

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
Restate: Is Restate open source?

The SDKs are MIT. The runtime is under a Business Source Licence, which permits self-hosting but not offering it as a competing service.

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
Restate: How does it compare with Temporal?

Same problem, different shape: one Rust binary with embedded storage instead of a server plus database plus workers, and lower per-step latency.

Keycloak: Is Keycloak free?

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

Source
Restate: Is there a free tier?

Yes, fifty thousand durable actions a month on Restate Cloud with no card required.

Restate: Which languages are supported?

TypeScript, Java, Kotlin, Go, Python and Rust.

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