Cafe / Restaurant Management System (FOH + BOH)
Deep modeling of a cafe/restaurant domain using Domain-Driven Design, Event Storming, CQRS, and Event Sourcing. Focus on Front-of-House (FOH) and Back-of-House (BOH) workflows: orders, tabs, kitchen, bar, service, and payments. No JavaScript; semantic HTML only.
Overview
This example models a cafe/restaurant where customers sit at tables, browse a menu, and receive food and drinks. FOH handles orders, service, and payments; BOH handles kitchen and bar preparation, inventory, and reporting. The system uses commands, events, and projections to coordinate complex workflows.
Domain Model (Key Building Blocks)
- Aggregates: Tab, Order
- Entities: Customer, Server, Table, MenuItem, Dish, Drink, KitchenTicket, Payment
- Value Objects: Location, TimeSlot, Price, Currency
- Domain Events: TabOpened, TableSeated, OrderPlaced, ItemAddedToOrder, OrderPrepared, DishReady, DishServed, PaymentProcessed, TabClosed
Commands
- OpenTab
- SeatCustomer
- PlaceOrder
- AddItemToOrder
- StartPreparation
- CompletePreparation
- ServeItem
- CloseTab
- ProcessPayment
Domain Events
- TabOpened
- TableSeated
- OrderPlaced
- ItemAddedToOrder
- OrderPrepared
- DishReady
- DishServed
- PaymentProcessed
- TabClosed
Read Models & Projections
- CurrentTabView
- OpenOrders
- KitchenQueue
- TableStatus
- RevenueByDay
Lifecycle Walkthrough
- Guest is seated and opens a tab (OpenTab, SeatCustomer).
- Server places initial drink/appetizer orders (PlaceOrder, AddItemToOrder).
- BOH starts preparation; KitchenTicket and DishReady events drive status updates.
- Food arrives; server serves items (DishServed) and updates tab/bill.
- Guest pays; TabClosed and PaymentProcessed events finalize the lifecycle.
Examples & Data Payloads
Conceptual payloads for orders and payments:
// OpenTab
{
"tabId": "tab_001",
"tableId": 12,
"customerId": "cust_745",
"openedAt": "2026-04-30T12:00:00Z"
}
// PlaceOrder
{
"tabId": "tab_001",
"orderId": "order_1001",
"items": [ {"menuItemId": "m_espresso", "quantity": 2}, {"menuItemId": "m_bagel", "quantity": 1} ],
"placedAt": "2026-04-30T12:02:00Z"
}
// PaymentProcessed
{
"tabId": "tab_001",
"amount": 15.75,
"currency": "USD",
"method": "CreditCard",
"paidAt": "2026-04-30T12:35:00Z"
}
Diagram & Illustration
