JavaScript (Node.js) and Microservices: From Monolith to Distributed Architecture

This book is a comprehensive practical guide to transitioning from a monolithic application to a flexible and scalable microservice architecture using JavaScript (Node.js). The author, Alexey Voronov, a senior developer with 10 years of experience, shares real-world cases and proven patterns that will help you avoid common mistakes at the start.

What is this book about?

The book is structured as an end-to-end project: you will start with a simple monolithic REST API on Express and step by step transform it into a system of several independent services. Each chapter is dedicated to a specific aspect of microservice development:

• Microservice Design: context boundaries, synchronous and asynchronous communication, protocol selection (HTTP/gRPC/AMQP).
• Containerization with Docker: creating a Dockerfile for Node.js, working with Docker Compose, orchestrating multiple services.
• Asynchronous Interaction: setting up RabbitMQ/Redis Pub/Sub, queue processing, guaranteed message delivery.
• Working with Data: Database per Service and Saga patterns (orchestration and choreography), choosing between MongoDB, PostgreSQL, and Redis.
• Testing and Monitoring: unit tests with Jest, integration tests for microservices, logging with Winston, and metric collection with Prometheus.
• Deployment and CI/CD: build automation with GitHub Actions, deployment on cloud platforms (AWS/Azure/Heroku), scaling.

Who is this book for?

The book is intended for developers with a basic knowledge of JavaScript (ES6+) and at least 6 months of experience with Node.js. It will be useful for both Junior developers who want to understand how modern backend systems work, and Middle-level specialists planning to implement microservices in their projects. If you work with Express/Koa and want to reach a new level of architectural solutions — this book is for you.

What will you learn?

• How to properly decompose a monolith into microservices without pain.
• When to use synchronous requests and when to use message queues.
• How to ensure data consistency between services (CQRS, Event Sourcing).
• How to set up Service Discovery (Consul) and API Gateway (Kong/Nginx).
• How to test microservices in isolation and in integration.
• How to automate deployment and monitoring of a production system.

The book contains over 50 code examples, ready-made Docker scenarios, and links to a repository with the complete project. All examples are tested under Node.js 18+ and are current as of 2024. Dive into the world of microservices with Node.js — and your applications will become flexible, fault-tolerant, and ready for scaling!