HTML to PDF. Perfectly.

CobaltPdf is a fast, fluent .NET 8 library that converts HTML pages and strings into pixel-perfect PDFs using a managed Chromium browser pool. Zero warm-up lag on subsequent requests, a clean chainable API, and first-class support for cookies, storage injection, custom JavaScript, fonts, watermarks, encryption, metadata, and cloud deployments.

---

Quick Start

using CobaltPdf;
using CobaltPdf.Configuration;

// One-time setup — call once at startup before any renders
// Use a CloudEnvironment preset for Linux, Docker, Azure, or AWS
CobaltEngine.Configure(CloudEnvironment.ConfigureForDocker);

// Render a URL
var renderer = new CobaltEngine();
var pdf = await renderer.RenderUrlAsPdfAsync("https://example.com");
pdf.SaveAs("output.pdf");

// Render an HTML string (in memory — no file written)
var pdf2 = await renderer.RenderHtmlAsPdfAsync("<h1>Hello World</h1>");
Console.WriteLine($"{pdf2.Length} bytes");

---

Highlights

Feature	Details
Browser pooling	Chromium instances kept warm between requests — no per-request startup cost
Fluent API	Chain options naturally: renderer.Landscape().AddCookie(…).RenderUrlAsPdfAsync(…)
Cloud presets	CloudEnvironment presets for Linux, Docker, Azure, and AWS in a single call
Wait strategies	Network idle, fixed delay, CSS selector, JavaScript expression, or manual signal
Cookie injection	Set cookies before navigation; domain auto-inferred after redirects
Storage injection	localStorage and sessionStorage populated before the page loads
Custom JavaScript	Execute arbitrary JS before capture; use window.cobaltNotifyRender() for precise control
Fonts	Point to a local directory — any .ttf, .otf, .woff, .woff2 file injected automatically
Headers & Footers	HTML templates with pageNumber / totalPages tokens
Watermarks	HTML overlay, fully positionable, with rotation and opacity
Encryption	User + owner passwords, print/copy/modify permissions
Metadata	Title, author, subject, keywords, creator embedded in the PDF
Lazy loading	Scroll N viewport-heights before capture to trigger infinite-scroll content
DI support	services.AddCobaltPdf(…) for ASP.NET Core / generic host
Microservice-ready	CobaltPDF.Requests companion package — clients send JSON payloads without installing Chromium
Licensing	Call CobaltEngine.SetLicense(key) to remove the trial watermark

---

Documentation

• Introduction — what CobaltPdf is and how it works
• Prerequisites — runtime requirements
• Chromium Setup — how Chromium is bundled and how to control it
• Getting Started — install and render your first PDF
• Configuration — global pool settings, cloud presets, and logging
• Rendering — URL, HTML string, and HTML file rendering
• Cookies & Storage — authentication and session flows
• Wait Strategies — controlling when the PDF capture fires
• Custom JavaScript — injecting scripts before capture
• Page Numbering — pageNumber / totalPages tokens
• Headers, Footers & Watermarks
• Fonts — custom local font injection
• Encryption — password protection and permissions
• Metadata — title, author, subject, keywords
• Lazy Loading — infinite-scroll and deferred content
• Dependency Injection — ASP.NET Core integration
• HTTP Requests — CobaltPDF.Requests microservice pattern, JSON schema, Azure Function and ASP.NET Core examples
• CobaltPDF.Requests — full property reference, Azure Function, AWS Lambda, ECS, and ASP.NET Core server examples
• Deployment — Docker, Azure, AWS, and Linux step-by-step guides
• Licensing
• API Reference — full generated reference docs