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Flagsmith vs Keycloak

Flagsmith logo

Flagsmith

Software Development

Open-source feature flag and remote config platform

From
Free
Rated
-
Full reviewWebsite
Keycloak logo

Keycloak

Developer Tools

Open-source identity and access management server.

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Flagsmith the Free plan supports only a single team member, limiting collaboration for small teams.; Keycloak requires self-hosted deployment and operational expertise to install, configure and maintain

Where they differ

Only the attributes on which Flagsmith and Keycloak actually diverge.

Attributes where Flagsmith and Keycloak differ
AttributeFlagsmithKeycloak
Pricing modelfreemiumopen-source
Platformsweb, apiSelf-hosted, Docker, Kubernetes, Linux, Windows, API
CategorySoftware DevelopmentDeveloper Tools

Identical on both: starting price (Free), 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 Flagsmith

  • Feature flags
  • Segments
  • A/B testing
  • Scheduled flags
  • SDKs
  • SAML/SSO

Only in Keycloak

Nothing recorded that Flagsmith does not also cover.

What people use each for

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

Flagsmith

  • Gradual feature rollouts across environmentsnot Keycloak
  • Remote configuration without redeploying codenot Keycloak
  • Running A/B tests tied to feature flagsnot Keycloak
  • Self-hosting feature flags for data residency requirementsnot Keycloak

Keycloak

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

Where each one falls short

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

Flagsmith

  • The Free plan supports only a single team member, limiting collaboration for small teams.
  • Exceeding request limits triggers overage charges after a one-time 30-day grace period.
  • Enterprise-grade SSO and governance are locked behind the Scale-Up and Enterprise tiers.
  • Self-hosting requires operating and updating the platform yourself, unlike a fully managed SaaS competitor.

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

Flagsmith

Free
  • FreeFree
    • Up to 50,000 requests/month
    • 1 team member
    • Unlimited feature flags, environments, identities and segments
  • Start-Up$45/month
    • Up to 1,000,000 requests/month
    • 3 team members
    • Scheduled flags, 2FA, A/B testing, integrations, email support
  • Scale-Up$300/month
    • 5,000,000+ requests/month
    • 5-20 team members
    • SAML/SSO, governance features, priority support

Keycloak

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

Which should you pick?

Choose Flagsmith if

  • You need feature flags.
  • You want to start without paying.
  • You work on web, api.
  • You also want segments.
Flagsmith 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 Flagsmith or Keycloak better?
Neither clearly leads. Flagsmith 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, Flagsmith or Keycloak?
Flagsmith starts at Free and Keycloak at Free.
Does Flagsmith or Keycloak run on more platforms?
Flagsmith runs on web, api. Keycloak runs on Self-hosted, Docker, Kubernetes, Linux, Windows, API.
Can I use Flagsmith for free?
Both have a free tier, so you can try either at no cost before committing.
What is Flagsmith best used for?
Flagsmith is most often used for gradual feature rollouts across environments, remote configuration without redeploying code, running a/b tests tied to feature flags, self-hosting feature flags for data residency requirements. Of those, gradual feature rollouts across environments and remote configuration without redeploying code are not what Keycloak is typically brought in for.
What can Flagsmith do that Keycloak cannot?
Flagsmith covers Feature flags, Segments, A/B testing, Scheduled flags.

Answered from the vendors’ own pages

Flagsmith: What does Flagsmith cost?

Flagsmith has a Free plan, a Start-Up plan from $40-45/month, a Scale-Up plan from $250-300/month, and custom Enterprise pricing.

Source
Keycloak: What protocols does Keycloak support?

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

Source
Flagsmith: Is there a free plan, and what are its limits?

The Free plan supports up to 50,000 requests per month and 1 team member, with unlimited feature flags, environments, identities and segments.

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
Flagsmith: How is usage metered?

Usage is metered by monthly API requests; exceeding a plan's limit triggers overage charges starting around $50 per million requests, with a 30-day grace period the first time a paid plan exceeds its limit.

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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