Backend Engineering — Concepts & Examples

A comprehensive reference guide documenting backend engineering concepts with working Express.js examples. Built as a personal learning repository.

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Table of Contents

#	Topic	Description
1	Authentication	JWT, Cookies, Sessions, OAuth
2	REST API	RESTful design, status codes, versioning
3	WebSockets	Real-time bidirectional communication
4	Caching	In-memory & Redis caching strategies
5	Rate Limiting	Protecting APIs from abuse
6	Password Hashing	bcrypt, argon2, best practices
7	File Upload	Multer, validation, storage
8	Pagination	Offset, cursor, and keyset pagination
9	Error Handling	Centralized error middleware

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Tech Stack

• Runtime: Node.js
• Framework: Express.js
• Auth: JWT, express-session, Passport.js
• Hashing: bcryptjs
• Uploads: Multer
• Rate Limiting: express-rate-limit
• WebSockets: ws / socket.io

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Getting Started

git clone https://github.com/YOUR_USERNAME/backend-engineering.git
cd backend-engineering

# Install dependencies for any topic
cd authentication/jwt
npm install
node index.js

Each folder is self-contained with its own package.json and README.md.

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📁 Repository Structure

backend-engineering/
├── authentication/
│   ├── jwt/
│   ├── cookies/
│   ├── sessions/
│   └── oauth/
├── rest-api/
├── websockets/
├── caching/
├── rate-limiting/
├── password-hashing/
├── file-upload/
├── pagination/
└── error-handling/

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