Hotel Room Booking System Sequence Diagram (Book a Room)

sequenceDiagram
  actor G as Guest
  participant W as Website
  participant B as Booking Service
  participant DB as Database
  participant P as Payment Gateway
  participant E as Email Service
  G->>W: Search dates and guests
  W->>B: Check availability
  B->>DB: Query free rooms
  DB-->>B: Available rooms
  B-->>W: Rooms and prices
  G->>W: Choose room and pay
  W->>B: Create booking
  B->>DB: Hold room for 10 minutes
  B->>P: Charge amount
  alt Payment successful
    P-->>B: Success
    B->>DB: Confirm booking
    B->>E: Send confirmation
    E-->>G: Booking email
  else Payment failed
    P-->>B: Failed
    B->>DB: Release hold
    B-->>W: Show payment failed
  end