AWS S05 L04 Implement Amazon Cognito OAuth 2.1 Login in React (Complete Code Walkthrough)

📘 IMPLEMENT AMAZON COGNITO OAUTH 2.1 LOGIN IN REACT (COMPLETE CODE WALKTHROUGH) In this lesson we walk through the complete React and TypeScript implementation of Amazon Cognito authentication using the OAuth 2.1 Authorization Code Flow with PKCE. Building on the theory from the previous lesson, we now follow the actual source code that powers a working authentication system. We examine every stage of the login process including state generation, PKCE code challenges, browser redirects, callback handling, token exchange, JWT decoding and user session management. By the end of the lesson you will understand exactly how a React application authenticates users with Amazon Cognito. --- 🎯 IN THIS VIDEO React authentication architecture Amazon Cognito login integration OAuth 2.1 Authorization Code Flow PKCE implementation State parameter generation Code verifier generation Code challenge generation SHA-256 hashing Browser local storage Redirecting users to Cognito Cognito callback handling Reading query string parameters Authorization code exchange Fetch API authentication requests Receiving ID tokens Receiving Access Tokens JWT token decoding React Context authentication state Managing authenticated users Building secure login flows --- 📦 TECHNOLOGIES COVERED React TypeScript Amazon Cognito OAuth 2.1 PKCE JWT Browser Storage Fetch API AWS CDK Vite --- 💻 WHY THIS MATTERS Many authentication tutorials explain OAuth conceptually but never show how the code is actually implemented. In this lesson we bridge that gap by tracing a real authentication flow through a working React application. You will learn: 1. How React initiates a Cognito login 2. How PKCE is implemented in code 3. How authorization codes are exchanged for tokens 4. How user information is extracted from JWT tokens 5. How authenticated user state is maintained across page reloads The same concepts apply to Amazon Cognito, Auth0, Azure AD, Okta and many other modern identity providers. --- 🌐 COURSE PORTAL https://richardbraycourses.co.uk --- 📂 COURSE REPOSITORY https://github.com/RichardBrayCourses... --- 📘 AWS SERVERLESS WEB DEVELOPMENT COURSE Build complete real-world AWS applications using: React → TypeScript → Express → Lambda → API Gateway → CDK → CloudFront → S3 → Cognito → PostgreSQL → DevOps