Convert HTML to PDF in C#

HtmlToPdfConverter turns HTML into a PDF without a browser: it builds a Word document and renders that. What comes through is what Word can express, so text, tables, lists and images survive, and flexbox and grid layouts do not.

using DocToolkit;

string html = "<h1>Invoice 2026-114</h1><p>Due on receipt</p>";
byte[] pdf = await HtmlToPdfConverter.ConvertAsync(html);
File.WriteAllBytes("output.pdf", pdf);

What it needs

No browser, headless or otherwise.
No Office install, and no LibreOffice.
No native files: managed code only.
No network at runtime, unless you ask for it.

Good to know

Asynchronous: ConvertAsync takes the HTML as a string and returns a Task<byte[]>.
Flexbox, grid, floats and absolute positioning are not applied, and unsupported features are dropped silently. The PDF is valid either way.
A4 by default; ConvertAsync(html, page) takes a PageSetup for another size.
Remote images are off by default. RemoteImageOptions turns them on per call, and by default still refuses loopback and private addresses (AllowPrivateAddresses opts in).

Install

dotnet add package Ank.DocToolkit

NuGet Documentation GitHub

Other conversions

Everything DocToolkit converts