Polymorphism, inheritance, encapsulation
Abstract Classes and Interfaces concepts (*)
MVC pattern
KISS, YAGNI, DRY principles (*)
Loose coupling and high cohesion concepts
Dependency injection (*)
Middleware concept
Experience with some Gang of Four design patterns (*)
Database Design patterns: Active Record, Data Mapper (*)
Refactoring techniques
PSR standards as a way to framework agnostic development (*)
- PSR-7 HTTP message interfaces
- PSR-15 HTTP Server Request Handlers
- PSR-3 Logger Interface
- PSR-6, PSR-16 Caching Interfaces
- PSR-18 HTTP Client
- PSR-14 Event Dispatcher
Tell Don't Ask principle
GRASP principles (*)
Domain Driven Development principles
- Learning OOP in PHP
- DesignPatternsPHP - List of all patterns with UML diagrams and examples