In this book, Pacifique Linjanja, a globally recognized software engineer and open-source contributor, shares his deep technical expertise and practical insights from his extensive experience delivering enterprise-level applications to unpack the full potential of NestJS, the cutting-edge Node.js framework. This book covers the core concepts, design patterns, and best practices for building scalable, high-performance applications with NestJS. You’ll learn REST API and GraphQL implementations, harness the power of microservices, and explore real-world case studies, including e-commerce, social networking, and ERP systems. The chapters provide step-by-step guidance for setting up your development environment with TypeScript and npm, structuring projects effectively, and using the Apollo Federation architecture to create efficient GraphQL APIs. This book offers hands-on guidance for testing and debugging APIs, handling exceptions, and validating data using pipes and guards, all while helping you build a complete NestJS application from scratch. By the end, you'll be ready to apply DevOps principles for continuous integration and deployment, as well as secure your NestJS applications using advanced techniques.