🖥️ Invoice Builder Backend

A RESTful backend API for the Invoice Builder full-stack project.
Built with Node.js, Express.js, and MongoDB, this backend handles invoices, clients, products, and company profiles, with validation, snapshotting, and automatic totals calculation.

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✨ Features

• 📄 Invoice Management

  • Create, edit, delete, and fetch invoices
  • Snapshot client & company details inside invoices
  • Automatic calculation of subtotal, taxes, fees, and grand total
  • Invoice status tracking (Draft, Paid, Unpaid)

• 👥 Client Management

  • Add, edit, delete, and fetch clients
  • Autofill invoices with saved client info

• 📦 Product Management

  • Add, edit, delete, and fetch products
  • Reuse products in invoices for consistency

• 🏢 Company Management

  • Store business details and logo
  • Used as default company profile in invoices

• 🧮 Smart Calculations

  • Real-time subtotal, tax, fee, and total calculation on server side
  • Ensures consistent results between frontend and backend

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⚙️ Tech Stack

• ⚡ Node.js + Express.js (REST API)
• 🍃 MongoDB + Mongoose (database & schema validation)
• 🔐 dotenv (environment variables)
• 🔄 CORS (cross-origin requests for frontend integration)
• 🛠 Nodemon (dev auto-reload)

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📂 Project Structure

backend/ ┣ 📂 controllers/ # Business logic for invoices, clients, products, company ┣ 📂 models/ # Mongoose schemas ┣ 📂 routes/ # Express routers for each resource ┣ 📂 utils/ # Helper functions (e.g., totals calculation) ┣ server.js # App entry point ┣ package.json ┗ README.md

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🔑 API Endpoints

Invoices

• GET /api/invoices → list all invoices
• GET /api/invoices/:id → get invoice by id
• POST /api/invoices → create new invoice
• PUT /api/invoices/:id → update invoice
• DELETE /api/invoices/:id → delete invoice

Clients

• GET /api/clients → list all clients
• POST /api/clients → create client
• PUT /api/clients/:id → update client
• DELETE /api/clients/:id → delete client

Products

• GET /api/products → list all products
• POST /api/products → create product
• PUT /api/products/:id → update product
• DELETE /api/products/:id → delete product

Company

• GET /api/company → get company profile
• PUT /api/company → update company profile

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🚀 Getting Started

1. Clone & Install

git clone https://github.com/yourusername/invoice-builder-backend.git
cd invoice-builder-backend
npm install

2. Setup Environment

Create a .env file in the root:

PORT=5000
MONGO_URI=your_mongodb_connection_string

3. Run Server

npm run dev   # with nodemon

Server runs at: http://localhost:5000

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📌 Notes

• Backend is designed to integrate with the Invoice Builder Frontend

• Totals are always computed on backend for consistency

• Client & Company snapshots are stored inside invoices for history

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🤝 What I Learned

• Structuring a modular Node.js + Express API

• Designing Mongoose schemas with nested snapshots

• Handling calculated fields on server instead of frontend only

• Building a backend ready for full-stack integration

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⚠️ Limitations & Future Improvements

• Authentication/authorization not implemented yet

• All data is stored in a shared MongoDB collection, so multiple users see the same data

• Plan: add JWT-based authentication and userId field to models to isolate data

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