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Identity vs KeyCloak

Last modified: Mar. 19, 2025 16:59
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Identity vs KeyCloak

Duende IdentityServer and Keycloak are both identity management solutions, but they differ significantly in architecture, ecosystem, and target use cases:

Protocol Support

Feature Duende IdentityServer Keycloak
Core Protocols OpenID Connect, OAuth 2.x OpenID Connect, OAuth 2.0, SAML 2.0
Token Types JWT/Reference tokens, Refresh tokens6 JWT, Opaque tokens, Refresh tokens37
Auth Flows Authorization Code, Client Credentials 20+ predefined flows including Device Flow

Architecture

Duende IdentityServer

  • Embedded .NET middleware for ASP.NET Core applications2

  • Requires manual implementation of user storage/management2

  • Primarily code-first configuration via C#26

Keycloak

  • Standalone Java-based server with admin web UI37

  • Built-in user federation (LDAP/AD sync)34

  • Visual configuration through admin console7

Enterprise Features

Capability Duende Keycloak
Multi-Factor Auth Custom implementation required Built-in TOTP/HOTP support3
User Federation Requires custom coding2 LDAP/AD sync out-of-the-box34
Social Logins Manual integration Pre-configured social providers3
Theme Customization Limited to ASP.NET Views Full HTML/CSS theming37

Licensing & Cost

  • Duende: Commercial license required for production use ($15k+/year)2

  • Keycloak: Apache 2.0 open-source license8

Development Experience

Duende Advantages

  • Tight ASP.NET Core integration26

  • Familiar C# configuration for .NET teams2

  • Fine-grained control over token contents6

Keycloak Advantages

  • Pre-built admin interface37

  • 150+ predefined authentication flows34

  • Built-in support for complex scenarios like step-up authentication3

Performance Considerations

  • Duende typically handles 2-5k RPS in .NET deployments6

  • Keycloak clusters can scale to 10k+ RPS with proper tuning48

Ideal Use Cases

Choose Duende When

  • Building .NET-centric applications requiring deep framework integration

  • Need lightweight identity services without Java ecosystem dependencies

  • Require complete control over authentication implementation26

Choose Keycloak When

  • Enterprise needs out-of-the-box IAM features47

  • Require social login or legacy protocol (SAML) support34

  • Need turnkey solution with minimal custom coding8

Both solutions support modern authentication patterns, but Keycloak offers more complete enterprise features while Duende provides deeper .NET integration capabilities237.

Citations:

  1. https://docs.duendesoftware.com/identityserver/v7/overview/specs/
  2. https://www.scottbrady.io/identity-server/getting-started-with-identityserver-4
  3. https://www.keycloak.org/docs/latest/server_admin/index.html
  4. https://www.bitcot.com/what-is-keycloak-and-how-does-it-work-for-business-security/
  5. https://supertokens.com/blog/supertokens-vs-keycloak
  6. https://docs.duendesoftware.com/identityserver/v7/tokens/overview/
  7. https://www.keycloak.org
  8. https://phasetwo.io/blog/open-source-iam/
  9. https://docs.duendesoftware.com/identityserver/v6/bff/overview/
  10. https://www.identityserver.com/products/adminui/feature-matrix
  11. https://hamidmosalla.com/2023/05/23/duende-identity-server-risks-of-sharing-clients-and-tokens/
  12. https://duendesoftware.com/products/features
  13. https://www.reddit.com/r/dotnet/comments/s3znz6/is_identityserver_the_goto_or_is_there_an/
  14. https://docs.redhat.com/en/documentation/red_hat_build_of_keycloak/22.0/html/server_administration_guide/red_hat_build_of_keycloak_features_and_concepts
  15. https://10decoders.com/blog/keycloak-use-cases/
  16. https://www.linkedin.com/pulse/keycloak-overview-its-advantages-ravi-kumar-srivastava

Answer from Perplexity: pplx.ai/share

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