Production-ready Node.js backend patterns with Express/Fastify, middleware, authentication, and database integration.

• Covers layered architecture (controllers, services, repositories), dependency injection, and microservices design with TypeScript
• Includes middleware patterns for authentication, validation, rate limiting, and request logging with practical examples
• Provides custom error handling, global error handlers, and async error wrappers for robust error management
• Supports PostgreSQL (connection pooling, transactions) and MongoDB (Mongoose) with caching strategies using Redis
• Demonstrates JWT authentication, refresh tokens, API response formatting, and best practices for production deployments