When you're building a Laravel application that scales beyond a few controllers and models, you’ll quickly feel the need for a cleaner, more maintainable architecture.

In this guide, I’ll walk you through 5 powerful patterns that can help organize your business logic:

1. Repository Pattern
2. Custom Query Builder
3. Service Class
4. Action Class
5. DTO (Data Transfer Object)

Let’s break each one down with examples 👇

✅ 1. Repository Pattern

Purpose:
Decouples your business logic from Eloquent, making your app easier to maintain and test.

Abstraction (Interface):

interface PostRepositoryInterface {
    public function all();
    public function find($id);
    public function create(array $data);
}

Concrete Implementation:

class PostRepository implements PostRepositoryInterface {
    public function all() {
        return Post::all();
    }

    public function find($id) {
        return Post::findOrFail($id);
    }

    public function create(array $data) {
        return Post::create($data);
    }
}

💡 Now you can inject PostRepositoryInterface anywhere and swap implementations later if needed (e.g., database vs API).

✅ 2. Custom Query Builder

Purpose:
Encapsulates complex or reusable query logic, keeping your code clean.

Class Example:

class PostQueryBuilder {
    public function published() {
        return Post::where('status', 'published');
    }

    public function byAuthor($authorId) {
        return Post::where('author_id', $authorId);
    }
}

🔁 You can inject this builder in services or controllers and chain queries like:

$postBuilder = new PostQueryBuilder();
$posts = $postBuilder->published()->get();

✅ 3. Service Class

Purpose:
Holds core business logic. Services call repositories or builders to perform operations.

Example:

class PostService {
    public function createPost(array $data) {
        return app(PostRepositoryInterface::class)->create($data);
    }

    public function listPublishedPosts() {
        return (new PostQueryBuilder())->published()->get();
    }
}

📌 Use services in controllers to reduce logic clutter and promote testability.

✅ 4. Action Class

Purpose:
Encapsulates a single operation, usually something that modifies state — like the Command Pattern.

Example:

class DeletePostAction {
    public function execute($postId) {
        Post::destroy($postId);
    }
}

⚡ Clear, focused, and testable. Perfect for things like CreateUserAction, UpdatePasswordAction, etc.

✅ 5. DTO (Data Transfer Object)

Purpose:
Structures and sanitizes data passed between layers of your app.

Example:

class PostDTO {
    public function __construct(
        public string $title,
        public string $content,
        public bool $published
    ) {}
}

🚀 Use DTOs to pass validated data from a controller to a service:

$postDto = new PostDTO('Title', 'Content', true);
$postService->createPost((array) $postDto);

These patterns are not Laravel-specific, but Laravel makes them easy to implement thanks to features like service container, contracts, and facades.

By adopting patterns like Repository, Service, and DTOs:

• ✅ You reduce controller bloat
• ✅ Your logic becomes reusable and testable
• ✅ Your codebase stays clean as it grows