Invoice Generator | APIVerve API Tutorial

A complete invoice generation application built with Node.js and Express. Create professional PDF invoices with a beautiful form interface.

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Features

• Professional PDF invoice generation
• Beautiful dark mode form interface
• Dynamic line items (add/remove)
• Auto-calculated totals
• Company and client details
• Custom notes and payment terms
• Downloadable PDF output
• Responsive design

Quick Start

1. Clone this repository

   git clone https://github.com/apiverve/invoice-generator-node-tutorial.git
   cd invoice-generator-node-tutorial

2. Install dependencies

   npm install

3. Add your API key

   Open src/config.js and replace the placeholder:

   API_KEY: 'your-api-key-here'

4. Start the server

   npm start

5. Open in browser

   Navigate to http://localhost:3000

Project Structure

invoice-generator-node-tutorial/
├── src/
│   ├── routes/
│   │   └── generate.js  # Invoice generation endpoint
│   ├── config.js        # API key and settings
│   └── index.js         # Express app setup
├── public/
│   └── index.html       # Frontend form and UI
├── package.json         # Dependencies
├── screenshot.jpg       # Preview image
├── LICENSE              # MIT license
├── .gitignore           # Git ignore rules
└── README.md            # This file

How It Works

1. User fills form - Enter invoice details, company info, line items
2. Submit to server - POST request to /api/generate
3. API call - Server sends data to APIVerve Invoice Generator
4. PDF generation - API creates professional PDF invoice
5. Download - User receives download link for the PDF

The API Call

const response = await fetch(API_URL, {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'x-api-key': API_KEY
  },
  body: JSON.stringify(invoiceData)
});

API Reference

Endpoint: POST https://api.apiverve.com/v1/invoicegenerator

Headers:

Header	Value
Content-Type	application/json
x-api-key	Your API key

Request Body:

{
  "invoiceNumber": "INV-001",
  "invoiceDate": "2024-01-15",
  "dueDate": "2024-02-15",
  "currency": "USD",
  "from": {
    "name": "Your Company Inc.",
    "email": "[email protected]",
    "address": "123 Business St, City, Country"
  },
  "to": {
    "name": "Client Company",
    "email": "[email protected]",
    "address": "456 Client Ave, City, Country"
  },
  "items": [
    {
      "description": "Web Development Services",
      "quantity": 10,
      "unitPrice": 150,
      "amount": 1500
    }
  ],
  "notes": "Payment due within 30 days. Thank you for your business!"
}

Example Response:

{
  "status": "ok",
  "error": null,
  "data": {
    "downloadURL": "https://storage.apiverve.com/invoices/abc123.pdf",
    "invoiceNumber": "INV-001"
  }
}

Use Cases

Invoice generation is essential for:

• Freelancers - Bill clients for projects
• Small Businesses - Create professional invoices
• SaaS Products - Generate subscription invoices
• Contractors - Invoice for hourly work
• E-commerce - Order receipts and invoices
• Service Providers - Bill for services rendered

Customization Ideas

• Add company logo upload
• Support multiple currencies
• Add tax calculation
• Email invoice directly to client
• Create recurring invoice templates
• Add payment status tracking
• Generate invoice from saved templates

Tech Stack

• Node.js - JavaScript runtime
• Express - Web framework
• Vanilla JS - Frontend (no framework needed)

Related APIs

Explore more APIs at APIVerve:

• QR Code Generator - Add QR codes to invoices
• HTML to PDF - Convert custom HTML to PDF
• Email Validator - Validate client emails

License

MIT - see LICENSE

Links

• Get API Key - Sign up free
• APIVerve Marketplace - Browse 300+ APIs
• Invoice Generator API - API details