FusionAuth
FreemiumAPI-driven CIAM platform with flexible deployment and total control
FusionAuth vs Keycloak
Objective factual benchmark between two leading platforms to identify optimal fit based on scale and architecture.
Keycloak
FreeOpen source identity and access management solution with single sign-on capabilities.
Technical Verdict & Decision Factors
FusionAuth provides an API-first architecture with commercial licensing and flexible deployment, whereas Keycloak offers a comprehensive open-source Java-based solution, requiring higher resource consumption but with no base licensing costs.
Scale-ups & Agile Teams
Choose FusionAuth if
Ideal for teams requiring a complete programmatic interface for CIAM automation, formal commercial support, and air-gapped deployments without open-source restrictions.
Get started with FusionAuth (opens in a new tab)Enterprise & Compliance
Choose Keycloak if
Optimal for teams with Java ecosystem expertise, restrictive budgets demanding pure open-source, and the capability to manage high-availability infrastructure.
Get started with Keycloak (opens in a new tab)Key Differentiators
- Licensing model: Commercial FusionAuth with a free tier vs. 100% open-source Keycloak under Apache-2.0.
- Tech stack and resource footprint: Java-based Keycloak with a higher memory footprint vs. API-optimized FusionAuth.
- Configuration management: FusionAuth prioritizes full API-driven automation, while Keycloak uses an admin console and Java SPIs.
FusionAuth7.1/10
Keycloak9.2/10
FusionAuth8.9/10
Keycloak8.9/10
FusionAuth5.3/10
Keycloak9.3/10
Side-by-Side Feature Comparison
| Datasheet | FusionAuthFreemium | KeycloakFree |
|---|
Commercial Model & Pricing
| Base Price | Free Tier | Free |
|---|---|---|
| Pricing Model | Freemium | Free |
| Score | ||
| Verified | VerifiedVerified tool: Audited technical attributes | VerifiedVerified tool: Audited technical attributes |
Core Features Matrix
| Specific Capabilities for Authentication & Identity Management (IAM) | ||
|---|---|---|
| Passkeys / WebAuthn Authentication | Not available | Not available |
| SCIM Provisioning | Compatible | Not available |
| Immutable Audit Logs | Not available | Not available |
| Real-Time Threat Detection | Not available | Not available |
| Enterprise Architecture & Security (7 Universals) | ||
| REST & GraphQL API | Compatible | Compatible |
| SSO / SAML Authentication | Compatible | Compatible |
| Self-Hosted Option | Compatible | Compatible |
| Full Data Export | Compatible | Compatible |
| Role-Based Access Control (RBAC) | Compatible | Compatible |
| Custom Domains & SSL | Compatible | Compatible |
| Immutable Audit Logs | Compatible | Compatible |
Architecture & Verified Specs
| Compliance & Data Sovereignty | ||
|---|---|---|
| Audited Certifications | ||
| SSO (SAML) Availability | Enterprise plan only | Included free |
| Legal Headquarters & Jurisdiction | US | US |
| Subject to US CLOUD Act | Subject (US Extraterritorial) | Immune (EU Sovereignty) |
| Data Residency | US, EU, SELF_HOSTED | SELF_HOSTED |
| Open Source Telemetry & Code Sovereignty | ||
| GitHub Stars | Proprietary / Closed Source | 37.6k |
| Latest Commit / Vitality | Proprietary / Closed Source | Oct 28, 2026 |
| SPDX License | Proprietary / Closed Source | Apache-2.0 |
| Primary Language | Cloud / SaaS | Java |
| Minimum RAM Required | Cloud Managed | Cloud Managed |
| Visit Website | Try FusionAuth (opens in a new tab) | Try Keycloak (opens in a new tab) |
|---|
Last technical review:
Technical Scorecard ComparisonShow detailsHide details
Technical Scorecard Comparison
Technical Scorecard Comparison: FusionAuth vs Keycloak
FusionAuth89/100
Keycloak90/100
DX & Tech Documentation+5 pts FusionAuth
Pricing Fairness+15 pts Keycloak
Security & Governance
Data Portability & Sovereignty+5 pts FusionAuth
Performance & Reliability
Time to Value & Fit by Segment: FusionAuth vs Keycloak
FusionAuth
Time-to-Value:1 - 7 days (Agile)
Curve:Moderate (Standard)
Standard sprint integration without complex external dependencies.
Keycloak
Time-to-Value:1 - 7 days (Agile)
Curve:Moderate (Standard)
Standard sprint integration without complex external dependencies.
Segment Fit Comparison
Pricing & Licensing BreakdownShow detailsHide details
Pricing & Licensing Breakdown
Billing Clauses & SSO Tax: FusionAuth vs Keycloak
FusionAuth
Enterprise-Only SSO
SAML/SSO locked strictly behind the highest custom corporate tier.
Free:Community edition is free for self-hosting with core auth features.
- Enterprise feature gates require contacting sales for higher tier pricing visibility.
Keycloak
Integrated Free SSO
SAML / OIDC available without extra charges or mandatory plan upgrades.
Free:Completely free and open source with unlimited usage when self-hosted.
TCO & Savings CalculatorTCO 1-3YShow detailsHide details
TCO & Savings CalculatorTCO 1-3Y
Usage Billing PredictabilityWhat usage costs as you scaleShow detailsHide details
Usage Billing PredictabilityWhat usage costs as you scale
Bidirectional Migration Friction Index (MFI)Show detailsHide details
Bidirectional Migration Friction Index (MFI)
Bidirectional Migration Friction Index (MFI)
Migration friction: FusionAuth to Keycloak
0/100
Agile transition with low operational risk and native export/API support.
Critical Factors Evaluated
Smooth path: native export support, ingestion API, and authentication parity.
Migration friction: Keycloak to FusionAuth
0/100
Agile transition with low operational risk and native export/API support.
Critical Factors Evaluated
Smooth path: native export support, ingestion API, and authentication parity.
Technical Transition Playbook: FusionAuth to KeycloakCLI Runbook4-stage execution protocol to switch dependencies with zero data loss and verifiable rollback.Show detailsHide details
Technical Transition Playbook: FusionAuth to KeycloakCLI Runbook
4-stage execution protocol to switch dependencies with zero data loss and verifiable rollback.Community Sentiment & Commercial TermsShow detailsHide details
Community Sentiment & Commercial Terms
Technical Reputation of FusionAuth
82/100 Technical Trust
Frequent Praises in Production
- Fully API-driven architecture for custom automation and workflows
- Self-hosted Docker container deployment for air-gapped environments
- Native support for modern authentication standards including passkeys
Reported Production Frictions
- Higher initial setup complexity compared to pure managed SaaS
- Advanced enterprise features require commercial license upgrades
Technical Reputation of Keycloak
91/100 Technical Trust
Frequent Praises in Production
- Completely open source with no commercial licensing fees.
- Native support for OpenID Connect, OAuth 2.0, and SAML 2.0 standards.
- Built-in identity brokering and social login integration.
Reported Production Frictions
- Requires significant memory and CPU resources for high-availability setups.
- Steep learning curve for advanced theme customization and custom SPI development.
Frequently Asked Questions: FusionAuth vs Keycloak
What are the key differences between FusionAuth and Keycloak?
FusionAuth provides an API-first architecture with commercial licensing and flexible deployment, whereas Keycloak offers a comprehensive open-source Java-based solution, requiring higher resource consumption but with no base licensing costs.
How do FusionAuth and Keycloak pricing compare?
FusionAuth starts at 0.00/mo under freemium tier, while Keycloak starts at 0.00/mo with free billing.
When should you choose FusionAuth over Keycloak?
If your priority is API-driven CIAM platform with flexible deployment and total control, FusionAuth is the optimal choice; for Open source identity and access management solution with single sign-on capabilities., Keycloak provides superior benefits.