NEXUS STORE: E-Commerce & Order Management
NEXUS STORE is a production-grade digital commerce platform connecting a responsive customer storefront with an executive admin management console. Powered by React 18, TypeScript, Node.js/Express, and PostgreSQL with Prisma ORM, the platform handles dynamic weight-based shipping calculation, instantaneous checkout via Midtrans Snap tokenization, cryptographic HMAC SHA-512 webhook validation, and dual-state inventory reservation.
Project Overview
Designed to solve inventory overselling during sales spikes and streamline post-purchase fulfillment. Customers experience a fast storefront with persistent carts, multi-address management, and verified buyer reviews, while administrators manage live order fulfillment, issue Airway Bills (AWB), configure discount promotions, and monitor sales trends with Recharts analytics.
The Problem
Traditional retail platforms face inventory race conditions where concurrent buyers purchase the same stock during promotions, unverified fake reviews, and insecure client-side order status updates.
The Solution
Built a dual-state stock reservation engine (dividing stock into available and reserved stock) with Prisma database transactions, server-side weight recalculation, verified buyer review constraints, and secure HMAC SHA-512 signature validation for Midtrans webhooks.
System Architecture
Decoupled architecture with React 18, Vite, and Tailwind CSS on the client side using TanStack Query for state caching and Recharts for BI visualization. The REST API is powered by Express.js and TypeScript, guarded by Zod schema validation, Helmet security headers, rate limiters, and Prisma ORM on PostgreSQL.
Key Technical Challenges
Preventing inventory overselling across high-traffic flash sales and guaranteeing idempotent payment confirmation via asynchronous webhook processing.
Lessons Learned
Separating physical inventory from reserved checkout allocations within atomic database transactions prevents concurrency conflicts, while server-side cryptographic signatures ensure bulletproof payment integrity.