An Identity Provider (IdP) verifies who you are and manages your login credentials. A Service Provider (SP) is the app or service you want to access, relying on the IdP to authenticate users securely. Together, they enable Single Sign-On (SSO), simplifying logins across multiple platforms.
Key Takeaways:
- IdP: Authenticates users and issues tokens (e.g., Google, Okta, Keycloak as IdP).
- SP: Validates tokens to grant access (e.g., Salesforce, Dropbox, Keycloak as SP).
- SSO Workflows:
- SP-Initiated: Login starts at the service app.
- IdP-Initiated: Login starts at the identity provider.
How Keycloak Handles Both Roles:
- As an IdP, Keycloak manages users, roles, and tokens for authentication.
- As an SP, Keycloak integrates with external IdPs, enabling identity brokering.
Quick Comparison
| Aspect | Identity Provider (IdP) | Service Provider (SP) |
|---|---|---|
| Role | Verifies user identity | Grants access to services |
| Examples | Google, Okta, Keycloak as IdP | Dropbox, Slack, Keycloak as SP |
| Function | Issues authentication tokens | Validates tokens for access |
Keycloak stands out by acting as both an IdP and SP, offering flexibility for managing secure user access. For a simpler setup, managed services like Skycloak can handle the infrastructure for you.
Main Differences Between Service Provider and Identity Provider
Identity Providers (IdPs) and Service Providers (SPs) are key players in single sign-on (SSO) systems, each with distinct roles. IdPs handle user authentication and issue tokens, while SPs validate these tokens to grant access to their applications or services.
SP vs IdP Roles Comparison
Here’s a breakdown of how these two entities differ, highlighting their distinct responsibilities and how they work together to enhance security and streamline user management:
| Aspect | Identity Provider (IdP) | Service Provider (SP) |
|---|---|---|
| Definition | Manages and authenticates user identities | Offers applications or services to users |
| Role | Verifies user identity and issues authentication tokens | Validates tokens and grants access to services |
| Examples | miniOrange, Okta, Microsoft Entra ID, Google Workspace | Salesforce, Dropbox, Slack |
| Function in SSO | Centralizes authentication for seamless SSO | Depends on the IdP for authentication and access validation |
| Data Managed | User credentials, permissions, and profiles | Application-specific resources |
| Security Responsibility | Protects user credentials and ensures secure authentication | Secures access to services based on IdP authentication |
For instance, if you log in to an app using a trusted identity service, the IdP verifies your credentials and issues a secure token. The app, functioning as the SP, accepts this token and grants you access.
SSO Flows: SP-Initiated vs. IdP-Initiated
The way SSO operates depends on how the process is initiated, which can happen in two ways:
- SP-Initiated SSO: The user starts by accessing an application (the SP), which redirects them to the IdP for authentication. Once authenticated, the IdP sends a SAML assertion back to the SP, allowing access. This flow is especially effective for consumer-facing apps and can reduce phishing risks by 60%, as users interact directly with trusted service providers. Organizations using this flow have also reported a 30% increase in compliance with standards like GDPR and HIPAA.
- IdP-Initiated SSO: The user logs into the IdP first, where they see a dashboard of available applications. Selecting an app prompts the IdP to send a SAML assertion directly to the SP, granting access. This approach is commonly used in enterprise settings where employees need access to multiple internal systems. However, it can be more vulnerable to man-in-the-middle attacks.
Choosing the right flow depends on your organization’s structure and user needs. SP-initiated SSO often provides better control over the login process and improves session management. It also contributes to a better user experience, with companies reporting a 30% drop in IT support tickets related to password issues when SSO is implemented effectively.
Grasping these differences is crucial when configuring tools like Keycloak to handle both IdP and SP roles efficiently.
How Keycloak Works as an Identity Provider
Keycloak simplifies user authentication by centralizing the management of credentials and issuing secure tokens. This approach allows organizations to maintain a unified authentication process while offering flexibility in how users access various services. Let’s walk through the steps to configure Keycloak as an Identity Provider (IdP).
Setting Up Keycloak as an IdP
To use Keycloak as your IdP, you’ll need to install the server and set up a realm.
Creating and Configuring Your Realm
Start by creating a realm, which serves as the foundation for managing authentication policies and client configurations. Keycloak supports both SAML and OpenID Connect protocols, allowing you to configure clients to receive secure tokens. These tokens are then validated by service providers, ensuring a seamless authentication process.
User Management and Role Configuration
Keycloak makes it easy to assign roles and groups to users, enabling fine-grained access control. It can integrate with LDAP or Active Directory, which is particularly helpful for migrating existing user data. You can define specific access levels for your applications and assign roles based on user responsibilities.
Attribute Mapping and Token Configuration
Mapping attributes ensures that user information is correctly passed on to service providers. This includes details like email addresses, department names, and roles. These attributes are then embedded into authentication tokens, making them accessible to connected applications.
For instance, one company successfully implemented single sign-on (SSO) across multiple systems by leveraging Keycloak’s OpenID Connect feature on a Kubernetes cluster.
Keycloak’s Identity Federation and Social Login Support
Once you’ve set up realms and defined user roles, Keycloak’s functionality can be expanded through identity federation. This feature enables integration with external identity providers, whether social platforms or enterprise systems, while still maintaining centralized access control.
Social Identity Provider Integration
To enable social login, register your Keycloak instance as an application with the desired social platform. For example, to integrate with Google, you’ll need to obtain OAuth client credentials from the Google Developer Console and configure them in Keycloak’s Identity Providers section. A similar process applies to platforms like Facebook and LinkedIn.
Enterprise Identity Provider Federation
In corporate settings, Keycloak can integrate with enterprise solutions like Microsoft Entra ID. This allows employees to use their existing corporate credentials across multiple applications. To set this up, create a new Identity Provider in Keycloak, configure the application in the Azure portal with the correct redirect URIs, and map the necessary scopes to extract user data.
LDAP and Active Directory Integration
When working with LDAP or Active Directory, you’ll need to configure connection settings such as the LDAP URL, base Distinguished Name (DN), and admin credentials. Keycloak maps LDAP user attributes to its own user model, ensuring consistent and accurate data across all connected systems.
Identity Provider Brokering
Keycloak also acts as an identity broker, enabling authentication through multiple IdPs simultaneously. Its Identity Provider Redirector feature can automatically send users to the appropriate external IdP based on predefined criteria, such as their email domain.
Security Considerations for Federation
Keycloak prioritizes security by supporting encryption and requiring HTTPS for all communications. Additionally, you can enforce multi-factor authentication (MFA) across federated identity sources, ensuring a consistent level of security no matter which IdP is used.
With Keycloak functioning as a reliable IdP, the next section will explore its capabilities when configured as a Service Provider.
How Keycloak Works as a Service Provider
Keycloak can also operate as a Service Provider (SP), allowing it to integrate with external authentication systems. This setup is especially useful for organizations that want to incorporate existing enterprise identity solutions while still benefiting from Keycloak’s advanced user management and access control features.
This approach creates a dynamic system where Keycloak handles user sessions and access permissions for applications but delegates the actual authentication process to trusted external providers.
Now that we’ve covered Keycloak’s role as an IdP, let’s look at how to configure it as an SP.
Setting Up Keycloak as an SP
Configuring Keycloak as a Service Provider involves enabling identity brokering, where Keycloak delegates authentication tasks to external Identity Providers (IdPs). Here’s how to set it up:
Creating the Client Configuration
Start by creating a new client in the Keycloak admin console to represent your application. Set the client protocol to “openid-connect” and define the valid redirect URIs where Keycloak will send authentication responses. If your application requires confidential access, adjust the access type accordingly and save the client secret for future use.
Configuring Identity Provider Settings
Navigate to the Identity Providers section in your Keycloak realm and add a new provider. If the external IdP offers metadata, Keycloak can auto-fill many required fields, simplifying the setup process.
| Configuration Option | Purpose |
|---|---|
| Alias | A unique identifier for building redirect URIs (e.g., corporate-sso, azure-ad) |
| Enabled | Activates or deactivates the provider |
| Store Tokens | Allows Keycloak to store tokens from the external IdP |
| Trust Email | Skips email verification for users from trusted IdPs |
| First Login Flow | Specifies the authentication steps for new users from this provider |
Setting Up Authentication Flows
Use the Identity Provider Redirector to guide users to the external IdP automatically. You can set a default identity provider for a smoother user experience or let users choose from multiple providers if needed.
Mapping External Identities
Ensure proper synchronization of external user attributes like email, username, and roles with Keycloak’s user model. Keycloak supports various synchronization modes, such as import-only, force-update, and legacy mapping strategies, to fit different needs.
For example, Gusto Engineering implemented this setup on March 10, 2025, using Keycloak as an identity broker. By consolidating multiple identity providers, they achieved seamless Single Sign-On (SSO) across various service provider applications. This approach centralized authentication logic within Keycloak, eliminating the need for code changes in individual applications.
When to Use Keycloak as an SP
Keycloak’s SP functionality shines in specific scenarios:
Enterprise and Multi-Tenant Integration
Organizations with existing enterprise identity solutions (like Microsoft Entra ID or SAML systems) or those supporting multiple clients can use Keycloak as an SP to unify application architecture. This setup accommodates diverse identity provider requirements across tenants and simplifies transitions during migration periods.
Regulatory and Compliance Needs
Industries that require certified identity providers for authentication can rely on Keycloak’s SP setup to meet these standards. Meanwhile, Keycloak continues to manage sessions, authorization policies, and user administration.
Legacy System Compatibility
For older systems that are difficult to replace, Keycloak serves as a bridge, connecting these legacy systems with modern authentication protocols. This enables gradual modernization without disrupting user workflows.
Social and External Provider Integration
Keycloak as an SP can also work with social identity providers like Google, Facebook, LinkedIn, and GitHub. This is particularly useful for customer-facing applications that need to support a variety of authentication options while maintaining consistent user management.
Conclusion
As we’ve explored, understanding the distinct roles of Service Providers (SPs) and Identity Providers (IdPs) is essential for designing secure and scalable authentication systems.
Keycloak stands out for its ability to function as both an IdP and an SP, offering flexibility for enterprise environments. This means organizations can use Keycloak to authenticate users for their own applications while also integrating seamlessly with external identity systems.
That said, this flexibility comes with operational challenges. Self-hosting Keycloak requires significant infrastructure and expertise, which can be a heavy lift compared to the managed services offered by Skycloak. Skycloak not only reduces costs but also provides enterprise-level features like 99.995% uptime, automated scaling, and advanced security measures – all without the operational burden.
For businesses implementing Identity and Access Management (IAM) systems, deciding between self-hosting and a managed solution like Skycloak is a pivotal choice. Skycloak allows organizations to unlock Keycloak’s full capabilities while freeing up teams to focus on their primary business goals. Whether you’re setting up a simple single sign-on system or managing a complex identity federation, understanding the roles of SPs and IdPs – and choosing the right deployment approach – ensures secure, scalable access for users while maximizing Keycloak’s potential and the convenience of managed services.
FAQs
What is the difference between an Identity Provider (IdP) and a Service Provider (SP), and how can Keycloak operate as both?
An Identity Provider (IdP) is responsible for verifying user identities and issuing identity tokens, while a Service Provider (SP) depends on the IdP to confirm those identities and grant access to its services. To put it simply, the IdP confirms who you are, and the SP uses that confirmation to let you access its resources.
Keycloak has the flexibility to handle both roles. As an IdP, it verifies users and issues tokens for other systems. At the same time, it can function as an SP by connecting to external IdPs, enabling smooth federation and single sign-on (SSO) across various platforms. This capability comes from its adaptable realm and client configurations, which support widely-used protocols like SAML and OAuth2 for secure authentication and authorization processes.
What security factors should I consider when using Keycloak as both an Identity Provider (IdP) and a Service Provider (SP)?
When using Keycloak as both an Identity Provider (IdP) and a Service Provider (SP), there are a few key security measures you should prioritize to maintain safe and dependable authentication workflows.
First, securing credentials is critical. Since authentication spans multiple systems, the chances of credential leaks or unauthorized access increase. To counter this, use strong encryption methods, ensure all communication happens over secure protocols like HTTPS, and enforce strict password policies.
Next, keep Keycloak updated to guard against vulnerabilities. Issues like flaws in SAML or OIDC validation logic can pose serious risks if not patched. Additionally, fine-tune Keycloak’s settings – such as attribute mapping and domain restrictions – to reduce exposure to potential threats.
Lastly, make regular security audits a habit and restrict access to sensitive configurations. These steps can go a long way in addressing risks tied to Single Sign-On (SSO) and integrations with external identity systems.
When is it better to use a managed service like Skycloak instead of self-hosting Keycloak?
Using a managed service like Skycloak makes a lot of sense if your organization prioritizes scalability, minimal maintenance, and compliance, all without stretching your IT resources thin. This approach is particularly helpful for small to medium-sized businesses or teams that want to stay focused on their main goals instead of dealing with infrastructure headaches.
With managed services, everything – infrastructure, updates, and security – is handled for you. This means you get a smooth, worry-free experience with dependable performance and uptime. On the flip side, self-hosting gives you more control and flexibility but comes with a heavier lift. It demands specialized skills, constant upkeep, and a hefty investment in infrastructure, which might not be the smartest option for every organization.