# Dependency Inversion Principle

Depend on interfaces, not on specific implementations.

## What is **Dependency Inversion Principle**?

The **Dependency Inversion Principle** says important code should depend on interfaces, not on specific tools. `OrderService` depends on `IEmailSender`, not on a particular email company.

```csharp
public class OrderService
{
    private readonly IEmailSender email;   // an interface, not SendGridClient
    public OrderService(IEmailSender email) => this.email = email;
}
```

Level: Freelancer · [More OOP terms at this level](https://www.ask-codey.com/glossary/subjects/oop/freelancer)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/dependency-inversion-principle