Secure Your Spring Boot App with Keycloak: A Beginner's Guide

🔐 Why Security Matters in Backend Applications

Security in applications means protecting your app, users, and data from threats.
Authentication verifies user identities, allowing systems to confirm who is trying to access their services, like logging into accounts. Authorisation ensures users can only perform actions aligned with their roles, enhancing security in the application.

IAM: Introduction and Problem Statement
Now the question comes: why do we need identity access management?
Imagine you are building a cool application or a cool web app, and in the entire system, you have 3 applications- website, admin dashboard, and mobile app. Now, how do users log in? How do you know who can do what? Do you want users to create an account for every application? Obviously not. You’d want to have 1 account, and that account should be shared across all the applications.
Another question is what if the user wants to log in using social methods, e.g, Google or Facebook.

Problems:-

• Security risks

• Integration nightmares

• Managing logins for every app

So the solution for all these problems is making use of an Identity and access management system.
Handle login, logout, and password reset.
Manage user roles(who is admin, who is viewer).
support social logins like Google or Facebook.
Keycloak is one of the Identity and access management systems and a popular choice for Java developers these days.

Some important Keycloak terms:
1. Realm→ A realm is like a workspace or a group inside Keycloak.
2. Clients→A client is just an application(web/mobile/api) that connects to keycloak for login.
3.Users→ These are your actual users. Employees, customers, admins, etc.
4. Groups: So groups in Keycloak represent a way to manage common attributes and role mapping for a set of users.
5. Roles→ Roles define permissions
6. OpenID→ It is an authentication protocol based on the OAuth 2.o framework
7. Oauth→ (Open Authorisation) is a standard protocol that allows users to grant third-party applications access to their information without sharing their passwords.

👩‍💻 Ready to Dive Into the Code?
Instead of cluttering this blog post with code snippets, I’ve created a fully working example that you can explore at your own pace.

✅ It includes:

• Spring Boot backend secured with Keycloak

• Role-based access to routes (/admin, /user)

• Keycloak setup with .properties configuration

• Example token decoding and testing with Postman

👉 Check out the full code on GitHub here:
KeycloakIntegrationCode

Final Thoughts
Implementing Keycloak in a Spring Boot application may seem tricky at first, but once set up, it saves you from reinventing the wheel, letting you focus on your app's logic, not the login system.
If you're just getting started with secure backend development or building microservices that need shared authentication, Keycloak is a fantastic tool to explore.