PHP Design Patterns Tutorial
A design pattern is a proven, reusable solution to a problem that keeps showing up in software design. Patterns aren't code you copy-paste — they're a shared vocabulary and a shape for a solution, first catalogued by the "Gang of Four" (GoF) in their 1994 book Design Patterns: Elements of Reusable Object-Oriented Software. This track covers the classic GoF patterns as they're commonly written in PHP.
Where this fits: This track assumes you're comfortable with Core PHP's OOP concepts (classes, interfaces, abstract classes) — if any of that feels shaky, the Core PHP track's OOP lessons are a good refresher first.
The Three Categories
| Category | What it's about |
|---|---|
| Creational | Controls HOW objects get created (Singleton, Factory Method, Abstract Factory, Builder) |
| Structural | Composes classes/objects into larger structures (Adapter, Decorator, Facade, Composite) |
| Behavioral | Manages communication and responsibility between objects (Strategy, Observer, Command, Iterator) |
A Quick Look Ahead
Example: The Problem Patterns Solve
// Without a pattern: creation logic scattered and duplicated everywhere
$logger = new FileLogger('/var/log/app.log');
// ...same setup repeated in five other files
// With the Singleton pattern: one shared instance, one place to configure it
$logger = Logger::getInstance();Note: These are correct, real PHP patterns — but this website's own project doesn't run them live, so you won't see interactive execution on these pages. Copy the examples into your own project to try them.
Why Learn Design Patterns?
| Reason | What it means for you |
|---|---|
| Shared vocabulary | Say "just use a Factory here" and every experienced developer knows exactly what you mean |
| Battle-tested solutions | Avoid reinventing (and getting wrong) solutions to problems others already solved well |
| Easier to read frameworks | Laravel, Symfony, and CakePHP all use these patterns internally — recognizing them helps you read framework source code |
| Better interviews | Design pattern questions are common in mid-to-senior PHP developer interviews |
Next steps: Head to Singleton to start with the simplest and most recognizable creational pattern.