When and Why to Use Contracts in Laravel

Imagine your application supports multiple payment providers:

• Razorpay
• Stripe
• PayPal

Instead of hardcoding one provider, define a contract.

Step 1: Create Contract

interface PaymentGateway
{
    public function charge(float $amount);
}

Step 2: Implement It

class RazorpayService implements PaymentGateway
{
    public function charge(float $amount)
    {
        // Razorpay logic
    }
}

Later, you can create:

class StripeService implements PaymentGateway
{
    public function charge(float $amount)
    {
        // Stripe logic
    }
}

Step 3: Bind in Service Container

$this->app->bind(PaymentGateway::class, RazorpayService::class);

Now Laravel automatically injects it.

Step 4: Use It Anywhere

public function store(PaymentGateway $payment)
{
    $payment->charge(500);
}

You can switch providers by changing only one binding line.

No controller changes needed.

🔹 Why Contracts Are Powerful

They:

• Reduce tight coupling
• Make swapping implementations easy
• Improve unit testing (mock interfaces easily)
• Keep architecture clean

🔹 When NOT to Use Contracts

Avoid contracts when:

• Logic is very small
• No chance of swapping implementation
• The app is extremely simple