👉 How to Secure Spring Boot Microservices with OAuth2 & JWT | Resource Server Explained (Video 28)

In this video, we design and implement the security backbone of our digital bank 🏦 — a shared Spring Boot security module that turns every microservice into a secure OAuth2 Resource Server.

Here’s what we cover:

🔐 Zero Trust Security Model – Every service independently validates JWT tokens.
🛡️ Commons-Security Module – A shared library that makes any microservice OAuth2-ready with one dependency.
⚙️ Spring Security Setup – DefaultSecurityConfig, SecurityFilterChain, JwtDecoder, and @PreAuthorize explained.
📦 Feign Token Relay – How tokens propagate automatically between microservices.
🧰 Real-World Patterns – Signature validation, issuer & audience checks, expiry, scopes, and permissions.

By the end, you’ll know how to build a reusable, production-grade security foundation for any microservices architecture — and never rewrite boilerplate again.