SOLID in Laravel.

SOLID in short

1/ S

(Single Responsibility Principle)

• A class should have only one job.

• Keep controllers and models thin.

• Move logic to services or traits.

2/ O

(Open/Closed Principle)

• Extend behavior without modifying existing code

• Use interfaces or abstract classes.

• Avoid editing core logic for new features.

3/ L

(Liskov Substitution Principle)

• Subclasses must work like their parent class.

• Methods should keep expected behavior.

• Avoid overriding with incompatible logic.

4/ I

(Interface Segregation Principle)

• Interfaces should be small and specific.

• No class should depend on unused methods.

• Split large interfaces into smaller ones.

5/ D

(Dependency Inversion Principle)

• Depend on interfaces, not concrete classes.

• Use Laravel’s Service Container for injection.

  • use Laravel’s Service Container

Common Laravel Mistakes That Violate SOLID

• Fat controllers violating SRP.

• Too much logic in Models

• Direct Database Queries in Controllers (Violates SRP & DIP)

• Not using contracts/interfaces, leading to tight coupling (DIP).

Laravel Tools & Features That Support SOLID

• Service Providers & Dependency Injection (DIP).

• Custom Requests

• Repositories & Interfaces (OCP, LSP).

• Middleware for separating concerns (SRP).

• Policies & Gates for clean authorization logic (SRP).