Ecommerce Startup API

A modular Node.js + Express REST API scaffold for users, products, and shopping carts — built for learning, interviews, and production-style growth.

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Table of contents

• Overview
• Features
• Architecture
• Tech stack
• Project structure
• Getting started
• API reference
• Example requests
• Roadmap
• Interview talking points
• Contributing
• License

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Overview

Ecommerce Startup API is a backend service that exposes REST endpoints for users, products, and per-user carts. The server uses Express middleware for JSON parsing and mounts feature routes under clear URL prefixes (/users, /products, /cart).

Current stage: Route handlers return placeholder responses. The structure (separate route modules, centralized server.js) is production-oriented and ready for controllers, validation, persistence, and auth.

Add a screenshot at docs/images/api-demo.png after running the server.

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Features

Area	Status	Description
REST routing	✅	Modular routers for users, products, cart
JSON body parsing	✅	express.json() enabled
Health / welcome	✅	GET / returns welcome message
Database	🔜	MongoDB / PostgreSQL (planned)
Auth (JWT)	🔜	Register, login, protected routes
Validation	🔜	Request schema validation (e.g. Zod/Joi)
Tests	🔜	Unit + integration (Jest/Supertest)
Docker / CI	🔜	Container + GitHub Actions

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Architecture

flowchart TB
  subgraph Client
    C[Web / Mobile / Postman]
  end

  subgraph Server["Express Server :3000"]
    S[server.js]
    S --> U["/users → userRoutes"]
    S --> P["/products → productRoutes"]
    S --> CART["/cart → cartRoutes"]
  end

  subgraph Future["Planned layers"]
    CTRL[Controllers]
    SVC[Services]
    DB[(Database)]
    U --> CTRL
    P --> CTRL
    CART --> CTRL
    CTRL --> SVC --> DB
  end

  C -->|HTTP JSON| S

Loading

Request flow (today):

1. Client sends HTTP request to Express.
2. server.js applies global middleware and mounts route modules.
3. Route handler responds (placeholder text until controllers/DB are added).

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Tech stack

Layer	Technology
Runtime	Node.js
Framework	Express 5.x
Module style	CommonJS (require)
API style	REST

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Project structure

ecommerce-startup/
├── server.js              # App entry: middleware, route mounting, listen
├── routes/
│   ├── userRoutes.js      # User CRUD-style endpoints
│   ├── productRoutes.js   # Product catalog endpoints
│   └── cartRoutes.js      # Cart per userId
├── package.json
├── package-lock.json
└── docs/
    └── images/            # README assets (banner, diagrams, screenshots)

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Getting started

Prerequisites

• Node.js 18+ (LTS recommended)
• npm (comes with Node)

Installation

git clone https://github.com/<your-username>/ecommerce-startup.git
cd ecommerce-startup
npm install

Run locally

node server.js

Server listens on port 3000:

Server is running on port 3000

Open http://localhost:3000 — you should see the welcome HTML message.

Environment variables (recommended next step)

Create .env (do not commit secrets):

PORT=3000
NODE_ENV=development
# DATABASE_URL=
# JWT_SECRET=

Update server.js to use process.env.PORT || 3000 when you add dotenv.

Suggested npm scripts (add to package.json)

"scripts": {
  "start": "node server.js",
  "dev": "node --watch server.js"
}

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API reference

Base URL: http://localhost:3000

Root

Method	Endpoint	Description
GET	/	Welcome message

Users (/users)

Method	Endpoint	Description
GET	/users	List all users (placeholder)
POST	/users	Create user (placeholder)
GET	/users/:id	Get user by ID (placeholder)

Products (/products)

Method	Endpoint	Description
GET	/products	List all products (placeholder)
POST	/products	Create product (placeholder)
GET	/products/:id	Get product by ID (placeholder)

Cart (/cart)

Method	Endpoint	Description
GET	/cart/:userId	Get cart for user
POST	/cart/:userId	Add item to user's cart

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Example requests

Welcome

curl http://localhost:3000/

Users

curl http://localhost:3000/users
curl -X POST http://localhost:3000/users -H "Content-Type: application/json" -d "{\"name\":\"Jane\"}"
curl http://localhost:3000/users/42

Products

curl http://localhost:3000/products
curl http://localhost:3000/products/101

Cart

curl http://localhost:3000/cart/42
curl -X POST http://localhost:3000/cart/42 -H "Content-Type: application/json" -d "{\"productId\":\"101\",\"qty\":2}"

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Roadmap

Production-minded milestones you can implement and mention in interviews:

• Layered architecture: routes → controllers → services → repositories
• Database: persist users, products, cart lines
• Auth: JWT + hashed passwords (bcrypt)
• Validation & errors: consistent { success, data, error } responses
• Security: helmet, rate limiting, CORS
• Observability: structured logging (pino/winston), health check /health
• Testing: Supertest integration tests per route
• Deploy: Docker + Render/Railway/Fly.io + GitHub Actions CI

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Interview talking points

Use this repo to demonstrate how you think about backend systems, not only syntax:

1. Separation of concerns — Route files isolate domains (users vs products vs cart); next step is controllers so routes stay thin.
2. REST design — Resource-oriented URLs; cart scoped by userId mirrors real e-commerce patterns.
3. Express middleware — express.json() for body parsing; global vs route-level middleware.
4. Scalability path — Stateless API → horizontal scaling behind a load balancer once sessions/JWT and DB are in place.
5. Trade-offs — Placeholder handlers ship fast for learning; production needs validation, idempotency on cart updates, and transactional inventory.
6. What you’d do next — Pick one vertical slice (e.g. POST /products with DB + tests) and complete it end-to-end — strong interview story.

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Contributing

1. Fork the repository
2. Create a feature branch: git checkout -b feature/amazing-feature
3. Commit changes with clear messages
4. Open a Pull Request

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License

This project is licensed under the ISC License — see package.json.

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Built with Express · Ready to grow into a production e-commerce backend