I Built an Invoice Generator in Pure HTML/CSS/JS — Here's Why

Hey devs!

I'm VAIBHAV, a self-taught developer from Greater Noida, India.

After paying ₹1,200/month for invoicing software I barely used, I decided to build my own.

What I Built

A fully client-side invoice generator that:

• Calculates GST automatically
• Generates PDFs with one click
• Works completely offline
• Stores data locally (privacy first)
• Runs on any device with a browser

The Stack

• HTML5
• CSS3 (no frameworks)
• Vanilla JavaScript
• html2pdf.js for PDF export

No React. No Node. No backend. Just a single HTML file that works everywhere.

Why This Matters

Most invoicing tools charge monthly subscriptions. For freelancers in India, that adds up.

I launched it on Gumroad for ₹1,250 one-time.

Try it: [your Netlify link]

Buy it: [your Gumroad link]

First 10 buyers get 50% off with code EARLY50.

The Code

The entire product is a single HTML file. Here's the core logic:

javascript
// Auto-calculate totals
function updateTotals() {
    const subtotal = items.reduce((sum, item) => sum + (item.qty * item.price), 0);
    const tax = subtotal * (taxRate / 100);
    const total = subtotal + tax;
    // Updates the invoice preview in real-time
}