Spring Boot Tutorial 0/110 lessons ~6 min read Lesson 46“Production-grade backends”

OAuth2 Basics

OAuth 2.0 is the standard for delegated authorization: "let users sign in with Google / GitHub without you holding their password." OpenID Connect (OIDC) adds an identity layer…

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Focus

3 guided sections

Practice signal

Examples included

Career prep

Foundation builder

Introduction

OAuth 2.0 is the standard for delegated authorization: "let users sign in with Google / GitHub without you holding their password." OpenID Connect (OIDC) adds an identity layer on top.

Syntax reference

Authorization Code flow with PKCE — the modern default:

bash

Browser            Spring App              Auth0 / Google
   │   GET /protected   │                          │
   ├───────────────────►│                          │
   │  302 to auth-server│                          │
   │◄───────────────────┤                          │
   │  GET /authorize ?code_challenge=...           │
   ├──────────────────────────────────────────────►│
   │  user logs in & consents                      │
   │◄────── 302 ?code=xyz ─────────────────────────┤
   │                                               │
   │  POST /callback (code)                        │
   ├───────────────────►│  POST /token (code+verifier) ►│
   │                    │◄────── id_token+access_token │
   │   set session/JWT  │                              │
   │◄───────────────────┤                              │

Informative example

bash

# application.yml — Spring Security as OAuth2 client
spring:
  security:
    oauth2:
      client:
        registration:
          google:
            client-id: ${GOOGLE_CID}
            client-secret: ${GOOGLE_SECRET}
            scope: openid,profile,email

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