Why should you care?

ShopNest “PlaceOrder” touches stock, payment, and email — controllers should not orchestrate all three in detail.

See it live — copy this example

Paste into a C# console or class library project and run dotnet run.

public sealed class StockOps { public void Reserve(string sku) => Console.WriteLine($"reserve {sku}"); }
public sealed class PaymentOps { public void Charge(decimal amt) => Console.WriteLine($"charge {amt}"); }
public sealed class MailOps { public void Send(string m) => Console.WriteLine($"mail {m}"); }
public sealed class CheckoutFacade
{
    private readonly StockOps _stock = new();
    private readonly PaymentOps _pay = new();
    private readonly MailOps _mail = new();
    public void PlaceOrder(string sku, decimal amount)
    {
        _stock.Reserve(sku);
        _pay.Charge(amount);
        _mail.Send($"Thanks for {sku}");
    }
}

new CheckoutFacade().PlaceOrder("HD-100", 4999);

Run Example »

Edit the code below and click Run to see the result in Toolliyo’s live editor.

What happened?

• CheckoutFacade sequences subsystems behind one method.
• Real systems inject dependencies and add transactions/sagas — the façade still keeps the entry point small.

Practice next

1. Call PlaceOrder and read the three lines.
2. Inject the ops via constructor.
3. Keep controllers calling only the façade/use-case.
4. Return an order id from PlaceOrder.
5. Add try/catch and compensate reserve on charge fail.

Remember

Simple front door. Hide subsystem churn. Keep it thin over time.

ShopNest checkout façade

API endpoint calls PlaceOrder use-case/façade.

Outcome: Controller stays ~5 lines.