Symfony Framework Guide

Applies to: Symfony 7+, PHP 8.2+, Doctrine ORM, Twig, Messenger

Core Principles

1. Convention Over Configuration: Follow Symfony defaults unless there is a strong reason not to
2. Dependency Injection: Constructor injection for all services; avoid service locators
3. Thin Controllers: Controllers delegate to services; no business logic in controllers
4. DTOs at Boundaries: Never expose Doctrine entities directly to API consumers
5. Events for Decoupling: Use EventDispatcher and Messenger for side effects
6. Explicit Configuration: Use PHP 8 attributes for routing, ORM mapping, and validation

Guardrails

Version and Dependencies

• Target Symfony 7.x with PHP 8.2+
• Use Composer with composer.lock committed