The Simplest Way to Integrate Keycloak with Spring Boot 3

Keycloak is a fantastic open-source Identity and Access Management tool, but integrating it into a Spring Boot application can sometimes feel overwhelming for beginners. In this quick guide, I'll show you the simplest way to secure your Spring Boot 3 REST APIs using Keycloak as an OAuth2 Resource Server. We will go straight to the code! Step 1: Add the required dependencies First, you don't need any complex Keycloak adapters anymore! Spring Security has built-in support for OAuth2 Resource Servers. Just add this to your pom.xml : <dependency> <groupId> org.springframework.boot </groupId> <artifactId> spring-boot-starter-security-oauth2-resource-server </artifactId> </dependency> <dependency> <groupId> org.springframework.boot </groupId> <artifactId> spring-boot-starter-web </artifactId> </dependency> Step 2: Configure application.yaml Next, tell Spring Boot where your Keycloak server is running. You only need to provide the issuer-uri of your Keycloak Realm: spring : security : oauth2