Roti Macan — E-commerce Bakery

Context & Problem

A bakery with busy pickup queues needed online ordering that never sells beyond production capacity per session and makes order handling easy for staff.

My Contribution

Built it end to end from scratch: database design, NestJS backend, Next.js storefront and dashboard, payment integration.

Solution & Key Features

• Per-session pickup quotas — time slots with capacity, enforced inside a database transaction.
• Fulfilment kanban — orders move across columns (paid → in progress → ready → picked up), worked on by several staff at once.
• Barcode scanner to verify pickups.
• BullMQ for async jobs: payment expiry and notifications.
• Midtrans payments with idempotent webhooks.

Architecture

flowchart LR
  C[Customer - Next.js] --> API[NestJS API]
  S[Staff Dashboard] --> API
  API --> DB[(PostgreSQL)]
  API --> R[(Redis)]
  R --> Q[BullMQ Workers]
  API <--> M[Midtrans]

Challenges & Decisions

• Quotas are checked with a row lock on the session slot, not in a cache, so the shop can never oversell.
• Payment webhooks are processed idempotently through a queue to survive gateway retries.

Outcome

Orders and pickups run without manual queueing; staff work in parallel on a single kanban board.