How to Convert HTML to PDF Automatically — Puppeteer and wkhtmltopdf

Use Cases

• Invoices and receipts: your app generates HTML, converts to PDF for the customer
• Dynamic reports: dashboards exported as PDF
• Certificates: diplomas and certificates generated automatically
• Documentation: HTML guides converted to PDF for download

Option 1: wkhtmltopdf (C++, Command Line)

# Install
sudo apt install wkhtmltopdf    # Ubuntu/Debian
brew install wkhtmltopdf         # macOS

# URL to PDF
wkhtmltopdf https://example.com/invoice/123 invoice.pdf

# Local HTML file to PDF
wkhtmltopdf page.html document.pdf

# With page options
wkhtmltopdf --page-size A4 --margin-top 20mm --margin-bottom 20mm page.html doc.pdf

# With custom header and footer
wkhtmltopdf --header-html header.html --footer-html footer.html page.html doc.pdf

Advantages: fast, no Node.js, works without a full browser. Limitations: old WebKit engine, limited modern JavaScript support.

Option 2: Puppeteer (Node.js, Headless Chrome)

npm install puppeteer

const puppeteer = require('puppeteer');
(async () => {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();
  await page.goto('https://example.com/invoice/123', { waitUntil: 'networkidle0' });
  await page.pdf({
    path: 'invoice.pdf',
    format: 'A4',
    margin: { top: '20mm', right: '15mm', bottom: '20mm', left: '15mm' },
    printBackground: true
  });
  await browser.close();
})();

Advantages: identical Chrome rendering, full modern CSS and JavaScript, web fonts. Limitations: downloads Chromium (~300 MB), slower on headless servers.

Option 3: PHP with DomPDF / Laravel

composer require barryvdh/laravel-dompdf

use Barryvdh\DomPDF\Facade\Pdf;
return Pdf::loadView('invoices.template', ['data' => $data])->download('invoice.pdf');

Tool Comparison

Tips for Quality PDFs from HTML

• Use @media print in CSS to adjust styles for print
• Use @page CSS to control page margins
• Use page-break-before: always to force page breaks
• Avoid position: fixed — causes pagination issues
• Use absolute URLs for images so the converter can find them
• Embed fonts with @font-face or use system fonts

Advanced Use Cases

Legal and business workflow: signed contracts are distributed in PDF/A (PDF Archival) which guarantees the document renders identically in 50 years — all fonts embedded, no JavaScript, no dynamic content. Electronic signature (PAdES, advanced eSignatures) is integrated in PDF and validates cryptographically. Academic publishing: theses and papers use LaTeX → PDF for precise mathematical formulas; journals require specific format (Word with styles, LaTeX with journal class, or both). Converting between LaTeX, DOCX and PDF preserving semantic structure (citations, references, equations) requires specialized tools like Pandoc. E-books: Amazon KDP requires MOBI (legacy) or KFX (modern) format generated from EPUB; Apple Books accepts EPUB natively; Kobo, PocketBook and Nook prefer EPUB; Google Play Books accepts PDF and EPUB. Converting DOCX manuscript to EPUB requires attention to semantic markup (hierarchical headings, lists, blockquotes) so reflowable layout works well. Translation workflows: professional translators prefer XLIFF as intermediate format — maintains segmentation, translation memory matches, and context info that is lost in plain text export.

Best Practices and Professional Tips

Style preservation: when converting between editable formats (DOCX↔ODT↔RTF), always use defined styles instead of direct formatting — Heading 1/2/3 vs "16pt Bold". This guarantees outline preservation and conversion maintains hierarchical structure. Font embedding: for cross-platform distribution (PDF), embed all non-standard fonts — without embedding, readers automatically substitute with available fonts which can break layout. PDF/A for archival: for legal, regulatory or permanent archive documents, export as PDF/A-1b (basic) or PDF/A-2u (Unicode + JPEG2000) — doesn't allow dynamic content, guarantees self-contained rendering. Revision history: PDF, DOCX and ODT support tracked changes and comments — when converting, decide if you want to preserve them (DOCX→DOCX or DOCX→ODT) or flatten them (DOCX→PDF typically accepts only the final state). Accessibility: PDF documents for public distribution should comply with PDF/UA — heading structure, alt text on images, defined reading order for screen readers.

Compatibility and Technical Considerations

KaijuConverter uses LibreOffice 7.6 headless as the main engine with Pandoc 3.x as fallback for complex markup conversions. We support more than 60 document formats (PDF, DOCX, DOC, ODT, RTF, TXT, HTML, MD, EPUB, MOBI, AZW3, FB2, LaTeX, RST and more). Format fidelity: we preserve fonts (with substitution fallback if original font is not on system), sizes, colors, complete paragraphs with indentation and line spacing, nested lists, tables with cell merging and complex borders, embedded images with anchor positioning, headers/footers with dynamic fields (page number, date, document title), footnotes and endnotes. PDF conversion: we guarantee PDF/A-conforming output when required, with correct font embedding and ICC profile embedding for absolute color fidelity. Limitations: documents with macros (DOCX with VBA) don't execute macros during conversion — only static content is preserved. Scanned PDFs (image without OCR) are not editable — they need previous OCR (Tesseract, ABBYY) to extract text. Privacy: TLS 1.3, isolated Docker containers, deletion after 2 hours. Performance: typical 20-page document takes 3-8 seconds; large documents with many images may require 15-30 seconds.

Related conversions

Document conversions that follow this topic naturally:

• PDF to DOCX
• DOCX to PDF
• MD to PDF
• HTML to PDF
• ODT to PDF
• PDF to TXT