Best way to conver HTML content in to PDF

Here are direct answers to your questions without extra framing.

1) Which libraries are best?

Best overall (recommended)

• PuppeteerSharp or Playwright for .NET
  These use a real Chromium engine, so they render HTML/CSS exactly like a browser. This is the most reliable and widely adopted approach today for HTML ? PDF.

Good alternative (simpler, commercial)

• IronPDF
  Easier setup, still Chromium-based, but paid.

Situational options

• QuestPDF
  Excellent if you are willing to build documents in C# instead of rendering HTML. Not suitable if your source is already HTML.

• iText7 (pdfHTML)
  Works for simpler HTML, but limited CSS support compared to browsers.

Not recommended for new work

• wkhtmltopdf (and wrappers like DinkToPdf)
  Outdated rendering engine, poor support for modern CSS (flexbox, grid), and no longer actively maintained.

2) Caveats (CSS support, A4 pagination)

CSS support

• Chromium-based tools (PuppeteerSharp / Playwright / IronPDF):

  • Full support for modern CSS (flexbox, grid, media queries, print styles)

  • Best fidelity with real browser output

• Non-browser engines:

  • Often fail with flexbox, grid, advanced layouts

  • Require workarounds or simplified HTML

A4 pagination

Regardless of library, correct pagination depends on your CSS.

Key rules:

@page {
  size: A4;
  margin: 20mm;
}

.page-break {
  break-before: page;
}

.no-break {
  break-inside: avoid;
}

Important points:

• Use @page to define A4 size and margins

• Use break-before, break-after, break-inside

• Avoid relying on pixel-perfect layout without print CSS

• Test with real content (long tables, images, etc.)

Common pitfalls

• Content overflowing due to missing margins

• Tables splitting awkwardly across pages

• Fonts not embedding correctly

• Differences between screen CSS and print CSS

3) Printing (silent vs dialog)

Show print dialog (simplest)

• Open the PDF with default viewer and trigger print:

Process.Start(new ProcessStartInfo {
    FileName = pdfPath,
    Verb = "print"
});

• This depends on the system’s default PDF viewer and shows UI.

Silent printing (recommended for production)

Option A: Use a PDF rendering library

• PDFium (via PdfiumViewer or similar)

• Load PDF and send directly to a printer:

using (var document = PdfiumViewer.PdfDocument.Load(pdfPath))
{
    using (var printDoc = document.CreatePrintDocument())
    {
        printDoc.PrinterSettings.PrinterName = "YourPrinter";
        printDoc.PrintController = new StandardPrintController(); // no dialog
        printDoc.Print();
    }
}

Option B: Use WebView2

• Load the PDF and call:

await webView.CoreWebView2.PrintAsync();

• Can be configured to suppress UI in some cases, but less predictable than PDFium.

Bottom line

• Use PuppeteerSharp or Playwright for HTML ? PDF.

• Control layout using proper print CSS (@page, page breaks).

• Use PDFium-based printing for reliable silent printing.

This combination is currently the most robust and production-proven approach for WPF applications.