PHP Application Architecture: From Chaos to Order

This book is a practical guide to creating well-designed PHP applications that are easy to maintain, extend, and test. The author, Alexey Petrov, a senior developer with 10 years of experience, shares proven approaches to architecture, saving the reader from typical mistakes and "spaghetti code."

Who this book is for

• Middle and Senior PHP developers who want to move from "just working code" to a well-thought-out architecture.
• Team Leads and Technical Architects looking for a systematic approach to organizing code within a team.
• Framework developers (Laravel, Symfony, Yii) who want to understand what happens "under the hood" and how to properly configure the project structure.

What you will learn

• The basic principles of SOLID and their application in real PHP projects.
• Design patterns (Factory, Repository, Strategy, Observer, and others) with examples in PHP 8+.
• Architectural styles: MVC, HMVC, Event-Driven, CQRS, and when to use them.
• Working with databases: Repository Pattern, Data Mapper, ActiveRecord, query optimization.
• Testing: unit, integration, and functional tests with PHPUnit and Pest.
• Dependency Injection and containers (PHP-DI, Symfony DI).
• Error handling, logging, and monitoring in a production environment.
• Migrating from legacy code to a modern architecture without a complete rewrite.

Book structure

The book is divided into four parts:

1. Foundation — basics of architecture, SOLID, patterns, Dependency Injection.
2. Application Layers — detailed breakdown of each layer: presentation, business logic, data access.
3. Scaling — caching, queues, microservices, handling high load.
4. Practice — step-by-step creation of a real application from scratch using best practices.

Each chapter contains code examples, diagrams, and self-assessment tasks. At the end of the book, there is a checklist for auditing an existing project and an architectural review template.

This book is not about PHP syntax — it is about thinking. After reading it, you will be able to design systems that do not "explode" at the first change in requirements, but easily adapt and evolve.

An ideal choice for those who are tired of rewriting code and want to do it right the first time.