C# HTML to PDF .NET library

CobaltPDF is a .NET library that converts HTML and live web pages into pixel-perfect PDFs in C#. It ships as two engines sharing one fluent API and one license key: CobaltPDF (Chromium) for maximum fidelity and the fastest renders on Windows and Linux, and CobaltPDF.WebKit for a lightweight, self-contained Linux engine with lower idle memory.

A managed warm renderer pool keeps throughput high under load, while built-in handling of cookies, client-side redirects, lazy-loaded images, web fonts, and wait strategies means real-world pages render correctly, not half-loaded. Add headers and footers, page numbers, watermarks, AES-256 encryption, metadata, and PDF splitting and merging from the same builder.

t targets .NET 8 and runs cleanly on Docker, Azure App Service, and Azure Functions. Free forever with a watermark: every feature, no time limit, even in production. A license key simply removes the watermark.