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Keycloak as an Identity Provider Broker (IdP)

What Is an IdP Broker?​

An Identity Provider (IdP) Broker acts as an intermediary between a service provider (your application) and multiple external identity providers (such as Google, Microsoft, or enterprise SAML/OIDC providers). It standardizes the authentication experience for users, regardless of which identity provider they use.

Keycloak, functioning as an IdP Broker, simplifies the integration of multiple identity sources into a unified system. It enables authentication across various identity providers while presenting a single, consistent entry point to users.

IdP Broker Use Cases​

IdP Brokers are especially useful in federated identity environments. Common use cases include:

  • Partner access to shared services in a B2B environment, where each partner uses their own IdP
  • Multi-organization platforms (e.g., SaaS tools) where each customer has their own enterprise IdP
  • Single entry point for diverse user bases, such as internal employees via SAML and customers via social logins
  • Simplifying integration with multiple social identity providers in B2C applications

By brokering identities, Keycloak enables users to authenticate using their preferred identity provider without the need for redundant credential management.

CIAM

Why Keycloak for IdP Brokering?​

Keycloak offers a flexible and robust IdP Brokering model that supports multiple protocols and use cases.

B2B Identity Federation​

Keycloak is well-suited for Business-to-Business (B2B) scenarios. It allows organizations to federate identities from:

  • Customer or partner IdPs
  • Other Keycloak instances (or between Keycloak realms on the same instance)
  • Standard-compliant IdPs using SAML or OpenID Connect

This supports secure, scalable authentication across business boundaries.

Phase Two simplifies this process and setup with our Organizations extension.

Protocol Translation & Normalization​

Keycloak acts as a bridge between various protocols, enabling:

  • SAML ↔ OIDC transformations
  • Standardized token issuance (e.g., JWTs for downstream services)
  • Role and attribute mapping between external IdPs and internal representations

Consistent Login Experience​

Keycloak consolidates the login flow into a single user-facing entry point, regardless of the upstream identity provider. This ensures a seamless experience and enables branding, language, and flow customizations.

Dynamic IdP Routing​

With Keycloak, you can configure:

  • Home realm discovery based on email domains
  • Pre-selected IdPs via URL parameters
  • Custom login flows to prompt users for IdP selection

This makes it easier to deliver tailored experiences for multi-tenant or partner-driven applications.

Phase Two simplifies this process and setup with our Organizations extension's home IdP discovery.

Account Linking & User Management​

Keycloak supports automatic or manual account linking, helping reconcile identities from different IdPs to a single user record. This is essential when users have accounts in multiple systems or migrate from one IdP to another.

By acting as a centralized broker, Keycloak simplifies the complexity of identity federation across diverse systems. It is a critical component for any organization that wants to provide secure, seamless access across multiple identity sources—without compromising user experience or security.