Overview of Keycloak and how it is used

Keycloak Overview

Keycloak is an open-source identity management solution that provides authentication and authorization functions for web applications and services. Its primary roles include the following features:

• Single Sign-On (SSO): With SSO functionality, users only need to log in once to access multiple applications without re-authenticating. This improves user experience and enhances security.

• Social Login Support: Keycloak integrates with external providers such as Google, Facebook, and Twitter, allowing users to conveniently log in using their existing accounts.

• User Authentication and Authorization: Keycloak offers detailed access control based on roles and groups, enabling strict resource management that aligns with corporate policies.

• Multi-Factor Authentication (MFA): By adding authentication steps such as one-time passwords or integration with smartphone apps, security can be further enhanced.

• Intuitive Web-Based User Management Interface: Administrators can easily add, edit, or delete users and configure permissions through a graphical interface.

• Support for Industry-Standard Protocols: Keycloak is compatible with OpenID Connect, OAuth 2.0, and SAML, ensuring safe and flexible integration with a wide range of applications and services.

Through these features, Keycloak provides a powerful and flexible foundation for identity and access management (IAM), making it an essential tool for enterprises and developers.

Keycloak Components

Keycloak consists of several components that enable flexible identity and access management. These elements are essential for achieving system scalability, multi-tenancy, and fine-grained access control.

• Realm: A Realm is the fundamental logical unit in Keycloak, used to isolate and manage users and clients (applications). For example, a company operating multiple services can create separate realms for each service, building completely independent authentication environments. This structure is also well-suited for multi-tenant configurations.

• User: A User refers to an individual registered in Keycloak who can log in. In addition to authentication credentials (such as username and password), users can be associated with metadata such as email addresses, attribute information, and group memberships.

• Client: A Client is an external application or service that integrates with Keycloak for authentication and authorization. Examples include web applications, mobile apps, and APIs. Protocols (such as OpenID Connect or SAML) and authentication flows can be configured individually for each client.

• Role: A Role defines access permissions that can be assigned to users or clients. For example, roles like “admin” or “user” can be created, each with different access rights, enabling flexible access control.

• Group: Groups are used to organize and categorize users, often in combination with roles. They are convenient for assigning common roles to multiple users at once and are suitable for managing organizational structures or teams.

By combining these components, Keycloak provides a robust framework capable of meeting diverse authentication and authorization requirements.

Advantages of Using Keycloak

By utilizing Keycloak, there is no need to build authentication and authorization mechanisms from scratch, which significantly improves both security and development efficiency. In particular, since Keycloak comes equipped with standard protocols and a wide range of features, it enables the rapid implementation of complex authentication infrastructures.

In addition, Keycloak provides an intuitive management UI, allowing administrators to visually manage users, configure roles, and register client applications directly from the browser. This makes management accessible even to those without deep technical expertise.

Furthermore, Keycloak offers flexible extensibility. Through the use of its Service Provider Interface (SPI), it is possible to add custom authentication logic and integrate with external systems, enabling tailored solutions to meet the specific needs of companies or projects.

Another major advantage is the ease of integration with external identity providers. Social login options, such as Google, Facebook, or Twitter, can be implemented with minimal configuration. Similarly, integration with external authentication platforms based on industry standards like SAML or OpenID Connect can be achieved through simple settings, ensuring seamless authentication across different systems.

Thanks to these benefits, Keycloak has been widely adopted by companies and development teams across various industries.

Practical Usage of Keycloak

Below are specific examples of how to use Keycloak in real-world scenarios:

Use Case ①: Implementing SSO for Web Applications

Objective:
Allow users to log in once and access multiple web applications (e.g., admin panels, user portals, APIs) without repeated authentication.

Architecture:

• Keycloak (Authentication Server)
• Web Application (React, Vue, Django, etc.)
• Keycloak JavaScript Adapter or OIDC Client

Steps:

1. Start Keycloak

docker run -p 8080:8080 \
  -e KEYCLOAK_ADMIN=admin \
  -e KEYCLOAK_ADMIN_PASSWORD=admin \
  quay.io/keycloak/keycloak:latest start-dev

2. Access the Admin Console
   • URL: http://localhost:8080
   • Login: admin / admin
3. Create a Realm
   • Example: my-realm
4. Register a Client (Application)
   • Client Name: my-web-app
   • Client Type: public
   • Redirect URI: http://localhost:3000/* (for React apps, etc.)
5. Create a User
   • Username: testuser
   • Set Password
6. Add Keycloak JS Adapter to Your App

npm install keycloak-js

7. Initialize Keycloak in Your Application (React Example)

import Keycloak from 'keycloak-js';

const keycloak = new Keycloak({
  url: 'http://localhost:8080',
  realm: 'my-realm',
  clientId: 'my-web-app'
});

keycloak.init({ onLoad: 'login-required' }).then(authenticated => {
  if (authenticated) {
    console.log("Login successful", keycloak.token);
    // Main application logic
  } else {
    console.log("Login failed");
  }
});

Use Case ②: Access Control for REST APIs Using JWT

Objective:
Protect backend APIs (Flask, FastAPI, Spring, etc.) with JWT token authentication.

Steps:

1. Register a Client in Keycloak (Type: confidential)
2. Obtain a Token:

curl -X POST http://localhost:8080/realms/my-realm/protocol/openid-connect/token \
 -H "Content-Type: application/x-www-form-urlencoded" \
 -d "client_id=my-api-client" \
 -d "username=testuser" \
 -d "password=xxxxx" \
 -d "grant_type=password"

3. Access the API with the Access Token:

curl -H "Authorization: Bearer <access_token>" http://localhost:8000/api/secure-data

4. Verify the Token on the API Side
   • In Python, you can use libraries like python-jose or authlib to validate the JWT.

Use Case ③: Login with Google Account (Social Login)

Objective:
Display a “Login with Google” button on the Keycloak login screen.

Steps:

1. Create an OAuth Client in Google Developer Console
   • Redirect URI Example:
     http://localhost:8080/realms/my-realm/broker/google/endpoint
2. Configure Keycloak:
   • Go to Identity Providers > Google
   • Enter the Client ID and Client Secret from Google
   • Update the Client settings to enable Google login

Use Case ④: Integration with External LDAP / Active Directory

Objective:
Unify corporate user accounts with Keycloak for SSO.

Steps:

1. In the Admin Console, go to User Federation > LDAP
2. Input Connection Details:
   • Host, Port, Bind DN, Base DN, etc.
3. Synchronization Settings:
   • You can enable periodic automatic synchronization to keep user data up-to-date.

These examples demonstrate how Keycloak can be used to secure applications and systems effectively with minimal setup.

Keycloak Practical Use Cases

1. Single Sign-On (SSO) Integration for Internal Systems
   Use Case:
   A company centralizes access to multiple internal web systems (attendance management, expense tracking, inventory, CRM, etc.) using Keycloak, enabling access to all apps with a single login.

Technologies Used:

• Keycloak + LDAP (Active Directory) integration

• Application integration via SAML / OpenID Connect

2. Authentication Platform for Customer-Facing Web Services
   Use Case:
   Implement user registration, login, password reset, and other features for web services (e.g., e-commerce sites, SaaS platforms) using Keycloak.

Key Benefits:

• Eliminates the need to build a custom authentication system

• Easily supports social login (Google, Facebook, etc.)

3. Mobile App Authentication Integration (iOS / Android)
   Use Case:
   Introduce OAuth2/OIDC token-based authentication for mobile apps and integrate with Keycloak.

Example Technology Stack:

• React Native + AppAuth + Keycloak

• Token-based API access control (authorization)

4. Integration with API Gateways (BFF Architecture / API Management)
   Use Case:

• Use JWT tokens to secure access to backend APIs

• Integrate Keycloak with Kong, Apigee, or Amazon API Gateway for token issuance and validation

Objectives:

• Client authentication and scope-based access control

• Protect against credential leakage

5. Identity Management for Multi-Tenant Environments
   Use Case:
   A SaaS provider separates user management and policies for each client (e.g., Company A, B, C).

Features:

• Isolation by realm

• Flexible configuration of user attributes and roles

6. User Authentication for Games and Community Platforms
   Use Case:
   Centralize user login, role management, and profile (avatar) management for games or community platforms.

Key Features:

• Device ID login and guest user registration supported

• User data retrieval and updates via REST API

7. Authentication Integration for Educational Systems (LMS)
   Use Case:
   Integrate Keycloak login with Moodle or other learning management systems.

Example Architecture:

• SAML / OIDC integration with university-wide authentication platforms (e.g., Shibboleth)

• Role-based access control based on positions (e.g., teacher, student)

8. Access Control for Healthcare Information Systems
   Use Case:
   Restrict access to patient information and system functions based on roles (doctor, nurse, administrative staff).

Key Features:

• High security with two-factor authentication and role-based access control

• Audit logging and token management

9. Authentication Testing Platform for Application Development
   Use Case:
   Use Keycloak as a lightweight SSO/authorization server during development. Easily launch it with Docker for testing purposes.

10. Identity Hub Integration with External Identity Providers
    Use Case:
    Connect multiple external services (Azure AD, Okta, Google) and use Keycloak as a centralized identity hub.

These use cases illustrate how Keycloak provides flexible, scalable, and secure identity and access management across various industries and application types.