HTML to PDF in C#

Updated July 2026 · HTTP client: HttpClient + System.Net.Http.Json — built into .NET

The shortest reliable path from HTML to PDF in C# is not a rendering library — it’s an HTTP call to a rendering API. Your app sends HTML, a managed Chromium engine renders it exactly as Chrome would, and a PDF comes back. No browser binaries in your deploy, no native dependencies, no page-break surprises.

Complete example (Program.cs)

Set NIPPYPDF_API_KEY in your environment, then this is the whole program:

// Program.cs (.NET 6+ top-level program) — run with: dotnet run
using System.Net.Http.Json;

using var http = new HttpClient { Timeout = TimeSpan.FromSeconds(30) };
http.DefaultRequestHeaders.Authorization = new(
    "Bearer", Environment.GetEnvironmentVariable("NIPPYPDF_API_KEY"));

var response = await http.PostAsJsonAsync("https://api.nippypdf.com/v1/pdf", new
{
    html = "<h1>Invoice #1042</h1><p>Total: $2,508.00</p>",
    format = "A4",
    margin = "20mm",
    print_background = true,
});

response.EnsureSuccessStatusCode();
await File.WriteAllBytesAsync(
    "invoice.pdf", await response.Content.ReadAsByteArrayAsync());
Console.WriteLine("Wrote invoice.pdf");

All request options

POST https://api.nippypdf.com/v1/pdf accepts JSON; the response body is the binary PDF. Options mirror Chromium’s print pipeline:

{
  "html": "<h1>…</h1>",              // or "url": "https://example.com/invoice/1042"
  "format": "A4",                     // "A4" | "Letter" | "Legal" | { "width": "210mm", "height": "297mm" }
  "margin": "20mm",                   // uniform, or { "top": "…", "right": "…", "bottom": "…", "left": "…" }
  "landscape": false,
  "scale": 1.0,                       // 0.1 – 2.0
  "print_background": true,
  "wait_until": "networkidle",        // "load" | "domcontentloaded" | "networkidle"
  "header_html": "<span></span>",     // running header (use sparingly)
  "footer_html": "<span class=\"pageNumber\"></span> / <span class=\"totalPages\"></span>"
}

For pagination control — keeping blocks together, repeating table headers, paper sizes — see the page-break CSS guide.

The self-hosted alternatives, honestly

• DinkToPdf / Rotativa: wrappers around wkhtmltopdf — an engine unmaintained since 2020, with native-library deployment headaches on Linux containers. Read more →
• PuppeteerSharp / Playwright .NET: Chromium output, plus a Chromium download and process management inside your app. Read more →

If those trade-offs are fine for your workload, they are honest choices. The API exists for teams who want Chrome’s output without operating Chrome.

FAQ

Try your own markup in the live in-browser demo, or jump to another language: Node.js, Python, PHP, Ruby, Go.