What is Keycloak?
Keycloak is an open-source Identity and Access Management (IAM) solution that provides user authentication, authorization, and user management for modern applications and services. It eliminates the need to store or authenticate users in applications by providing single sign-on (SSO), identity brokering, social login, and user federation capabilities.
Created by Red Hat and part of the WildFly application server ecosystem, Keycloak supports standard protocols like OAuth 2.0, OpenID Connect (OIDC), and SAML 2.0. It provides a complete solution for securing applications, APIs, and microservices with features like multi-factor authentication, password policies, and fine-grained authorization.
Keycloak Capacity Calculator
CPU Cores: 2
DB Storage: 10GB
Security Score: 85/100
Keycloak Core Components
Realms
Isolated spaces for managing users, roles, and applications.
• Separate user stores
• Independent configurations
• Multi-tenant support
• Cross-realm trusts
Clients
Applications that request authentication from Keycloak.
• Mobile apps
• API services
• Public/confidential types
• Protocol mappers
Users & Groups
User accounts and organizational structures.
• User attributes
• Group hierarchies
• Group membership
• Federated users
Roles & Permissions
Authorization and access control mechanisms.
• Client roles
• Composite roles
• Role mappings
• Fine-grained permissions
Keycloak Authentication Features
Single Sign-On (SSO)
Users authenticate once and gain access to multiple applications.
2. Redirected to Keycloak for authentication
3. User provides credentials and authenticates
4. User accesses Application B
5. Automatically authenticated (SSO session exists)
6. User gains access without re-entering credentials
Multi-Factor Authentication
• SMS authentication
• Email verification
• Hardware tokens
• Biometric authentication
• Conditional MFA
Social Login
• Facebook Login
• GitHub authentication
• LinkedIn login
• Custom identity providers
• Account linking
User Federation and Identity Brokering
LDAP/Active Directory
Connect to existing enterprise user directories.
• Active Directory integration
• User synchronization
• Group mapping
• Attribute mapping
• Password delegation
Custom Providers
Integrate with custom user stores and systems.
• REST API integration
• Database connections
• Legacy system integration
• Custom authentication
• Migration support
Identity Brokering
Delegate authentication to external identity providers.
• OpenID Connect providers
• Token exchange
• Account linking
• First login flows
• Trust relationships
User Storage
Flexible user storage and management options.
• Federated storage
• Read-only sources
• Caching layers
• Offline users
• Import strategies
Protocol Support and Integration
OpenID Connect
Modern authentication protocol built on OAuth 2.0.
• Implicit Flow
• Hybrid Flow
• Client Credentials
• JWT tokens
• Dynamic registration
SAML 2.0
Enterprise standard for federated identity.
• Service Provider (SP)
• Metadata exchange
• Assertion encryption
• Attribute statements
• Single logout
OAuth 2.0
Authorization framework for API access.
• Refresh tokens
• Scope management
• Client authentication
• PKCE support
• Token introspection
Real-World Keycloak Implementations
European Central Bank
Uses Keycloak for secure access to financial systems and regulatory compliance.
- • Multi-factor authentication
- • Regulatory compliance
- • Federated identity
- • Audit logging
Lufthansa
Leverages Keycloak for employee and customer identity management across systems.
- • Employee SSO
- • Customer portals
- • Mobile applications
- • Partner integrations
MIT
Uses Keycloak for academic and research platform authentication.
- • Student authentication
- • Research platform access
- • LTI integration
- • Federated research
Bosch
Implements Keycloak for IoT device authentication and industrial applications.
- • IoT device authentication
- • Industrial applications
- • Supply chain systems
- • Partner ecosystems
Keycloak Best Practices
✅ Do
- • Use HTTPS for all Keycloak communications
- • Implement proper backup and disaster recovery
- • Configure strong password policies
- • Enable audit logging and monitoring
- • Use realm separation for multi-tenancy
- • Implement MFA for administrative accounts
- • Regular security updates and patches
❌ Don't
- • Use default credentials in production
- • Skip SSL/TLS configuration
- • Ignore performance tuning for large deployments
- • Store sensitive data in custom attributes
- • Bypass security policies for convenience
- • Neglect database security and backups
- • Mix development and production realms