Spring Security

Integrating Keycloak with Spring Boot for OAuth2 resource server protection is one of the most searched tasks in the IAM developer community — yet most tutorials stop at “hello world” level. This guide covers production-grade integration: JWT validation, Keycloak realm role extraction, multi-tenant setups, and integration testing strategies. Clone the companion repo: All working code in this guide is available at github.com/IAMDevBox/keycloak-spring-boot-oauth2 — includes Docker Compose for Keycloak, complete Spring Boot 3.x application, and integration tests with Testcontainers. ...

I’ve configured SAML SSO for 30+ Spring Boot applications. The setup looks simple in docs, but production always throws curveballs - certificate mismatches, signature validation failures, attribute mapping issues. Here’s what actually works. Visual Overview: sequenceDiagram participant User participant SP as Service Provider participant IdP as Identity Provider User->>SP: 1. Access Protected Resource SP->>User: 2. Redirect to IdP (SAML Request) User->>IdP: 3. SAML AuthnRequest IdP->>User: 4. Login Page User->>IdP: 5. Authenticate IdP->>User: 6. SAML Response (Assertion) User->>SP: 7. POST SAML Response SP->>SP: 8. Validate Assertion SP->>User: 9. Grant Access Clone the companion repo: Get the full working source code with Docker Compose (Keycloak as IdP), multi-IdP config, custom attribute mapping, and integration tests: github.com/IAMDevBox/spring-security-saml-example ...