Living Systems Handbook microservices as humans
Bipin Singh
Pilot: Café Sukoon

Meet Café Sukoon

2 min readChapter 27 of 34By Bipin Singh

Sukoon means "peace of mind". Café Sukoon is our pilot project: a small café whose staff are microservices. It's simple enough to build in a weekend, yet it uses every idea in this handbook — and it can live all three lifestyles.

The story

  1. A customer scans the QR code on their table, opens the menu (the café's senses — a web UI) and places an order.
  2. The Waiter takes the order, remembers it and announces OrderPlaced.
  3. The Chef hears the announcement, creates a kitchen ticket and starts cooking. When the dish is ready, the kitchen staff tap "ready" and the Chef announces OrderReady.
  4. The Cashier hears OrderPlaced, prepares the bill, and when the customer pays, announces PaymentCompleted.
  5. The Messenger hears OrderReady and PaymentCompleted and tells the customer: "Your chai is ready!", "Thanks — here's your receipt."

The humans

Human One job Senses (inputs) Voice (events) Memory
Waiter Take and track orders POST /orders, GET /orders/{id} OrderPlaced Orders table
Chef Prepare food OrderPlaced (inbox); POST /kitchen/tickets/{id}/ready OrderReady Tickets table
Cashier Collect money OrderPlaced (inbox); POST /payments PaymentCompleted, PaymentFailed Bills table
Messenger Talk to customers OrderReady, PaymentCompleted (inbox) — Sent-messages table (with TTL)

The shared world

Shared piece Service
Senses of the society (UI) Static web app on S3 + CloudFront
Front door API Gateway HTTP API
Town square EventBridge custom bus
Customer identity (later) Cognito
History books Firehose → S3 → Athena

Architecture at a glance

QR menu (S3 + CloudFront)
        │ HTTPS
        ▼
API Gateway "front door"
   ├── /orders ─────────────► Waiter ──OrderPlaced──┐
   ├── /kitchen/tickets/... ─► Chef                  │
   └── /payments ───────────► Cashier                ▼
                                        EventBridge "town square"
                       ┌────────────────────┼───────────────────────┐
                       ▼                    ▼                       ▼
               SQS chef-inbox      SQS cashier-inbox      SQS messenger-inbox
                       ▼                    ▼                       ▼
                     Chef                Cashier                Messenger
               (OrderReady) ─────────────────────────────────────────┘

The build plan

Chapter You build
Hiring the Waiter The Waiter, with a lifestyle setting, on the shared world
The kitchen comes alive Chef, Cashier and Messenger, wired through the town square
A day in three lifestyles The same café configured for chilling, peace and the rat race — and load-tested
Running the café Monitoring, costs, cleanup and ideas to extend it
Tip

Build it in a sandbox AWS account and set an AWS Budget alert first. Everything here is serverless and cheap at low volume — but load tests and forgotten provisioned concurrency are not free.

Bipin Singh
Written by Bipin Singh

Senior Full-Stack Engineer · AI & AWS. I design and build serverless systems on AWS — and love explaining them simply.

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