DEV Community: Jack Green

Building a 100% Client-Side PDF Invoice Generator with jsPDF (No Backend, No Sign-Up)

Jack Green — Thu, 02 Jul 2026 03:28:02 +0000

Freelancers send a handful of invoices a month, yet most invoicing tools charge a monthly subscription. I wanted the opposite: a tool you open in a browser, fill in, and get a professional PDF — no account, no server, no data leaving your machine.

Here's how I built it, and the interesting problems along the way.

The constraint that shaped everything: no backend

The entire app is static files: one HTML page, some CSS, and four small JS modules. PDF generation happens in the browser with jsPDF plus the autoTable plugin for line items.

That constraint buys three things for free:

Privacy — client names and amounts never touch a server.
Offline — it works with WiFi off; useful on trains and planes.
Zero hosting cost — it's static, so it deploys anywhere.

Generating the PDF

The core is surprisingly small. jsPDF gives you a canvas-like imperative API, and autoTable handles the line-item table with automatic pagination:

const doc = new jspdf.jsPDF();
doc.setFontSize(22);
doc.text('INVOICE', 14, 22);

doc.autoTable({
  startY: 60,
  head: [['Description', 'Qty', 'Rate', 'Amount']],
  body: items.map(i => [i.desc, i.qty, fmt(i.rate), fmt(i.qty * i.rate)]),
  theme: 'striped',
});

doc.save(`invoice-${number}.pdf`);

The details that took actual time:

Currency formatting — Intl.NumberFormat handles symbols and thousands separators correctly for every locale, so don't hand-roll it.
Long descriptions — autoTable wraps cell text, but you need columnStyles with fixed widths or totals drift off the page edge.
Totals section — drawn manually after the table using doc.lastAutoTable.finalY as the anchor.

Templates with localStorage

Freelancers invoice the same clients repeatedly, so the app saves templates as plain JSON in localStorage — again, no server:

localStorage.setItem('invoice-template-' + name, JSON.stringify(formState));

One catch: localStorage is per-origin, so if you later move domains, saved templates don't follow. Export/import as a JSON file covers backup.

Dark mode without a toggle

CSS custom properties plus prefers-color-scheme means the app follows the OS setting with zero JS:

:root { --bg: #ffffff; --ink: #111827; }
@media (prefers-color-scheme: dark) {
  :root { --bg: #0f172a; --ink: #e2e8f0; }
}

The PDF itself always renders light — invoices get printed, and toner is expensive.

The business experiment

I'm selling this the boring way: a $9 one-time purchase (via Creem, a merchant-of-record, so VAT is handled). The free demo generates 5 watermarked invoices; the paid version is the same app, unlocked, delivered as a ZIP you own forever. No subscription, because charging monthly for a tool that runs entirely on your computer feels wrong.

Free demo (no email, nothing): https://invoice.jackgreen.top/app.html?utm_source=devto&utm_medium=article&utm_campaign=invoice-launch
Product page: https://invoice.jackgreen.top/?utm_source=devto&utm_medium=article&utm_campaign=invoice-launch

If you try it, I'd genuinely like to hear what breaks or what's missing — comments here are perfect.

I Built a CSV Data Cleaner That Saves Hours — Free Tool

Jack Green — Wed, 24 Jun 2026 21:40:12 +0000

Why CSV Cleaning Matters

Every data analyst and developer has faced this: messy spreadsheets with duplicates, wrong date formats, encoding issues, and trailing spaces.

The Solution: CSV Cleaner

I built a free web tool that cleans CSV files in seconds:

Remove duplicates
Standardize dates
Fix encoding
Trim whitespace
And 5 more operations

Try it: http://23.27.134.52:3000

How It Works

Drag-drop your CSV file
Select cleaning operations
Download the clean file

All processing happens in your browser — no data leaves your computer.

Get the Pro Version

Need CLI access and priority support? Get the CSV Cleaner Pro on Gumroad for just .

How to Make Money as a Developer in 2026 — 4 Paths That Actually Pay

Jack Green — Wed, 24 Jun 2026 10:05:24 +0000

How to Make Money as a Developer in 2026

The old path — learn to code, get a job — is fading. Today, developers build multiple income streams.

1. Freelance Work

Fiverr and Upwork let you find clients immediately. Specialize in Stripe integrations or API development and charge 0-150/hr.

2. Digital Products

Sell UI kits and templates on Gumroad. I built a Stripe Dashboard UI Kit — 15 components, 9. Gumroad handles payment, delivery, and VAT.

3. Micro-SaaS

Build a small tool, charge -50/month. Use my free Stripe Checkout Generator to add payments in 10 minutes.

4. Affiliate Revenue

Write about tools you love. DigitalOcean gives 5 credit per referral. SiteGround pays 0-100.

Start Building

Pick one path and ship this weekend. Need a dashboard UI? Grab the kit for 9.