PHP Guide

Applies to: PHP 8.1+, Web Applications, APIs, CLIs, Microservices

Core Principles

1. Strict Types Always: Every PHP file starts with declare(strict_types=1)
2. Type Declarations Everywhere: All parameters, return types, and properties must have type declarations
3. PSR Standards: Follow PSR-12 coding standard, PSR-4 autoloading, PSR-7 HTTP messages
4. Composition Over Inheritance: Prefer interfaces, traits, and dependency injection over deep class hierarchies
5. Modern PHP First: Use PHP 8.1+ features (enums, readonly properties, fibers, named arguments, match expressions)

Guardrails

Version & Dependencies

• Target PHP 8.1+ (enums, readonly properties, fibers, intersection types)
• Define all dependencies in composer.json with version constraints
• Run composer validate and composer audit before committing