# Paid. Then sold out.

> The last room went to another site first.

- **Format:** short video, 10 steps, ~57 seconds
- **Topic:** How hotel booking confirmation works — why the last room can sell on another site after a traveller has paid, and how authorizing the payment, booking with the supplier and capturing only after confirmation means a sold-out room never needs a refund.
- **Author:** Suthahar Jegatheesan (MSDEVBUILD)
- **Category:** Architecture · Design Pattern
- **Published:** 2026-10-03
- **Tags:** systemdesign, traveltech, payments, sagapattern, azure, azureservicebus, softwarearchitecture, backenddeveloper, dotnet, interviewprep, msdevbuild
- **Canonical URL:** https://blog.msdevbuild.com/shorts/hotel-booking-sold-out-after-payment/

---
## What you'll learn

- Why every booking site can sell the same last hotel room
- Why you authorize a payment at Pay and capture it after the supplier confirms
- What to do when the supplier does not answer at all

## Understand it one step at a time

### 1. One room, two sites

The last sea-view room for the long weekend, shown on your app and on another site.

### 2. The other site is first

At 21:13:56 another site books it. Your app still shows one room left.

### 3. Pay first, ask later

Your traveller is charged ₹13,688 at 21:14:05. Then the booking goes to the hotel.

### 4. A week-long refund

Every sold-out room becomes a refund that takes 5 to 7 working days.

### 5. Nobody can lock the room

Only the hotel owns the room. Every site sees a copy that is seconds to minutes late.

### 6. Hold, don't charge

At Pay, authorize the amount: the bank sets it aside, nothing is taken.

### 7. Sold out? Void the hold

The supplier says SOLD_OUT. Release the hold. Nothing charged, nothing to refund.

### 8. Confirmed? Now capture

The traveller picks a similar room. The supplier confirms, and only then is the hold charged.

### 9. No answer? Ask again

A timeout is not a no. Keep the hold and look the booking up by your own reference.

### 10. Hold the money, charge after the room

Price check, authorize, book, then capture or void. Reconcile anything unanswered.

---

## The takeaway

**Hold the money. Charge after the room.**

Authorize at Pay, book with the supplier, capture on confirmation, void on sold out.