Car Wash Management System

A full-stack management system built for a real car wash business. Handles orders, sales, inventory, and payments. I was packaged as a desktop app, but designed so it can move to the cloud when the business scales.

Tech Stack

Layer	Technologies
Frontend	React 19, Vite, TanStack Query, React Router, Tailwind CSS
Backend	Node.js, Express, Prisma, SQLite
Desktop	Electron
Shared	TypeScript, Zod, npm workspaces

Features

• Dashboard — KPIs, revenue charts, activity feed, and inventory alerts
• Orders — Kanban board with columns for state (Pending → In Progress → Completed)
• Sales & Purchases — Transaction tracking with full history
• Inventory — Stock management with adjustment reasons (damage, theft, expiry)
• Multi-currency — USD / VES / EUR support with live BCV exchange rates
• Settings — Store info, payment methods, and exchange rate configuration

Architecture

Monorepo with three apps and one shared package:

apps/
  api/        # Express REST API
  web/        # React frontend
  desktop/    # Electron wrapper
packages/
  types/      # Shared DTOs, schemas, and enums

The API follows a layered architecture: Controllers → Services → Repositories, with a manual dependency injection container. The shared types package keeps API contracts in sync with the frontend without any code generation.

In production, Electron spawns the Node.js API as a utility process and loads the bundled web app — everything ships as a single desktop installer.

Key Decisions

Node.js + React instead of a monolithic stack The client needed a desktop app first, but wanted the option to go cloud later. Splitting the frontend and backend from day one made that a straightforward path — just deploy the two apps separately when the time comes.

SQLite + Prisma Zero-config database for the desktop phase. Switching to PostgreSQL is a one-line change in the Prisma schema.

Monorepo with shared types Avoids duplication between API and web. Both apps import the same DTOs and validation schemas, so a change in one place propagates everywhere.

Getting Started

Requires Node.js 20+.

cp apps/api/.env.example apps/api/.env
npm install
npm run dev

This starts all three apps concurrently (API, web, and Electron).

What I Learned

• How to apply clean architecture (layered pattern + DI container) in a real Node.js backend
• Structuring a monorepo with npm workspaces and cross-app shared packages
• Managing server state with React Query — caching, invalidation, and keeping the UI in sync
• Talking with a real client, mapping their business processes, and translating that into technical requirements