Back to case studies

Case Study

trendy

An API built with NestJS and PostgreSQL for a multi-role logistics/marketplace platform connecting customers, stores, and drivers. It covers the full order lifecycle from cart to delivery with pickup/drop-off tasks, driver assignment by zone, speed, and availability, real-time notifications, and order status tracking. It includes product catalog management, media assets, reviews, and admin analytics for orders and revenue.

Role: Backend + DeploymentStatus: ProductionRepo: Private
  • Multi-role logistics/marketplace API covering the cart-to-delivery flow.
  • Driver assignment by zone/speed/availability with task-based pickup and delivery.
  • Catalog + media management, Firebase push notifications, and admin analytics.

Stack: NestJS • PostgreSQL • TypeORM • JWT • Cloudinary • Firebase • Docker

Overview

This project is an API for a multi-role logistics/marketplace platform connecting customers, stores, and drivers.

It covers the full order lifecycle from cart to delivery, including pickup/delivery tasks, driver assignment by zone, speed, and availability, real-time notifications, and order status tracking.

It includes product catalog management, media assets, reviews, and admin analytics for orders and revenue.

My Role

  • I designed and built the NestJS backend.
  • I modeled PostgreSQL using TypeORM.
  • I implemented RBAC and auth flows (JWT + Refresh Token via HTTP-only cookie + Google OAuth).
  • I implemented the order lifecycle and driver tasks logic.
  • I integrated Cloudinary signed uploads and Firebase push notifications.
  • I prepared Docker-based staging/production setup and a health endpoint.

Stack

  • NestJS (TypeScript)
  • PostgreSQL
  • TypeORM
  • JWT + Refresh Token via HTTP-only cookie + Google OAuth
  • Cloudinary signed uploads
  • Firebase push notifications
  • Docker (staging/production)
  • Health endpoint
  • External USD-rate API

API Highlights

Auth & Users

  • Email signup/login, code verification, and password recovery.
  • Google OAuth and Refresh Token via HTTP-only cookie.
  • RBAC (admin/seller/driver/customer) with admin user activation.

Catalog

  • Hierarchical categories with speedType (fast/slow) affecting delivery speed.
  • Products with colors/sizes, return window, and availability.
  • Media (images/video) with Cloudinary signed uploads, store logos, and driver photos.

Shopping Experience

  • Cart items store a snapshot of the product at purchase time for stable pricing/data.
  • Favorites.
  • Separate ratings for product/seller/driver (one rating per customer per target).

Orders & Logistics

  • Order creation from cart with customer profile validation; delivery speed is inferred from product categories.
  • Slow orders require time windows; fast orders have no window.
  • Seller-level item confirmation/rejection with a 15-minute window and auto-reject on timeout.

Order statuses

PENDING›CONFIRMED›READY_FOR_DELIVERY›PROCESSING›SHIPPED›DELIVERED

Exceptions

RETURN_REQUESTEDCANCELLED

Driver Tasks

  • Orders split into PICKUP/DELIVERY tasks.
  • Assign the least-busy driver by zone, speed, and availability while preventing overlapping time windows for the same driver.
  • Task status updates drive order status, with pickup and delivery confirmation via delivery code.
  • Customer and seller tracking.

Notifications

  • Device registration and Firebase push notifications.
  • Admin broadcast messaging.

Admin Analytics

  • Summaries for orders, revenue, and users.
  • Top stores and drivers.
  • Time-series charts for orders and revenue.

Supporting Services

  • External USD-rate API.
  • Health endpoint.
  • Dockerized staging/production.