How do I generate invoices as PDFs from my app?

To generate invoices as PDFs from your app, the usual flow is:

1. Create invoice data
   Build an invoice object with fields like customer name, line items, taxes, totals, invoice number, date, etc.

2. Render it into HTML or a PDF template
   Most apps generate an invoice as:

   • HTML/CSS first, then convert to PDF, or
   • a server-side PDF document directly using a PDF library.

3. Convert to PDF Use a tool/library depending on your stack.

Common approaches

Option 1: HTML/CSS → PDF

Best if you want invoices to look like normal web pages.

• Node.js: Puppeteer, Playwright
• Python: WeasyPrint, wkhtmltopdf
• PHP: Dompdf, mPDF
• Ruby: Grover, WickedPDF
• Java: OpenHTMLtoPDF

Example flow:

• Generate an HTML invoice template with your data
• Render it in a headless browser
• Save/download the resulting PDF

Option 2: Direct PDF generation

Best if you want precise control and don’t need HTML.

• Node.js: PDFKit
• Python: ReportLab
• Java: iText, Apache PDFBox
• .NET: QuestPDF, iText

This gives more control but usually takes more layout work.

Example: Node.js with Puppeteer

const puppeteer = require('puppeteer');

async function createInvoicePdf(html, outputPath) {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();
  await page.setContent(html, { waitUntil: 'networkidle0' });
  await page.pdf({
    path: outputPath,
    format: 'A4',
    printBackground: true,
    margin: { top: '20mm', right: '15mm', bottom: '20mm', left: '15mm' }
  });
  await browser.close();
}

Example: Python with ReportLab

from reportlab.lib.pagesizes import A4
from reportlab.pdfgen import canvas

def create_invoice_pdf(path):
    c = canvas.Canvas(path, pagesize=A4)
    c.drawString(100, 800, "Invoice #1001")
    c.drawString(100, 780, "Customer: Acme Corp")
    c.save()

Things to include in an invoice PDF

• Invoice number
• Your business details
• Customer details
• Issue date / due date
• Line items
• Subtotal, tax, discounts, total
• Payment instructions
• Branding/logo
• Terms and conditions

Best practices

• Keep a server-side copy of the generated PDF
• Use a stable template so invoices don’t shift visually
• Embed fonts if you need consistent rendering
• Generate PDFs asynchronously if volume is high
• Store a record of the exact invoice data used

If you want the simplest setup

If your app already uses HTML/CSS, the easiest path is usually:

• design an invoice page in HTML/CSS
• render it with a headless browser like Puppeteer/Playwright
• export to PDF

If you tell me your tech stack, I can give you a ready-to-use example.