COMPARISON

HTMLDOC vs IronPDF: Technical Comparison Guide

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This comparison looks at both tools across relevant technical aspects to assist developers and architects in making informed choices for their .NET PDF needs.

Understanding HTMLDOC

HTMLDOC is an older HTML-to-PDF converter with origins in the dot-com era. It was initially developed before CSS became a key part of web design, using a custom HTML parser from the 1990s that supports HTML 3.2 with limited CSS features. The tool operates solely through command-line interfaces, requiring process spawning from .NET applications.

HTMLDOC needs the external executable to be installed on the target system. All interactions use ProcessStartInfo to call the command-line tool with flags like --webpage, --size, --header, and --footer. For HTML string input, HTMLDOC requires writing content to temporary files first, then passing the file path as an argument.

The tool is available under the GPL license, which has viral characteristics—any software incorporating GPL code must also be released under the same open-source license. This presents challenges for commercial software development.

Understanding IronPDF

IronPDF is a native .NET library designed for developers who need HTML-to-PDF conversion within the .NET ecosystem. The library uses a modern Chromium rendering engine, providing accurate rendering of HTML5, CSS3, JavaScript, and modern layout systems like Flexbox and Grid.

IronPDF installs via NuGet package (Install-Package IronPdf) and provides direct API access through the ChromePdfRenderer class. Methods like RenderHtmlAsPdf(), RenderHtmlFileAsPdf(), and RenderUrlAsPdf() handle different input types. Configuration uses RenderingOptions properties for paper size, margins, headers, and footers. The library works directly with HTML strings in memory—no temporary files required.

IronPDF offers a commercial license that allows integration into proprietary software without the complications associated with GPL licensing.

Architecture and Integration Comparison

The main difference between these tools lies in their integration architecture and rendering capabilities.

FeatureHTMLDOCIronPDF
Rendering EngineCustom HTML parser (1990s)Modern Chromium
HTML/CSS SupportHTML 3.2, minimal CSSHTML5, CSS3, Flexbox, Grid
JavaScriptNoneFull execution
.NET IntegrationNone (command-line)Native library
Async SupportNoFull async/await
LicenseGPL (viral)Commercial (permissive)
MaintenanceMinimal updatesActive development
SupportCommunity onlyProfessional support
DeploymentInstall binaryNuGet package

HTMLDOC's command-line architecture requires process spawning, temporary file management, shell escaping, and exit code handling. This adds complexity and potential failure points in server environments. IronPDF's native .NET integration eliminates these concerns with direct method calls and standard exception handling.

Code Comparison: Common PDF Operations

HTML File to PDF Conversion

The most fundamental operation demonstrates the architectural differences.

HTMLDOC:

// HTMLDOC command-line approach
using System.Diagnostics;

class HtmlDocExample
{
    static void Main()
    {
        // HTMLDOC requires external executable
        ProcessStartInfo startInfo = new ProcessStartInfo
        {
            FileName = "htmldoc",
            Arguments = "--webpage -f output.pdf input.html",
            UseShellExecute = false,
            RedirectStandardOutput = true,
            CreateNoWindow = true
        };

        Process process = Process.Start(startInfo);
        process.WaitForExit();
    }
}
// HTMLDOC command-line approach
using System.Diagnostics;

class HtmlDocExample
{
    static void Main()
    {
        // HTMLDOC requires external executable
        ProcessStartInfo startInfo = new ProcessStartInfo
        {
            FileName = "htmldoc",
            Arguments = "--webpage -f output.pdf input.html",
            UseShellExecute = false,
            RedirectStandardOutput = true,
            CreateNoWindow = true
        };

        Process process = Process.Start(startInfo);
        process.WaitForExit();
    }
}
$vbLabelText   $csharpLabel

IronPDF:

// NuGet: Install-Package IronPdf
using IronPdf;

class IronPdfExample
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlFileAsPdf("input.html");
        pdf.SaveAs("output.pdf");
    }
}
// NuGet: Install-Package IronPdf
using IronPdf;

class IronPdfExample
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlFileAsPdf("input.html");
        pdf.SaveAs("output.pdf");
    }
}
$vbLabelText   $csharpLabel

HTMLDOC requires creating a ProcessStartInfo object, configuring the executable path, building command-line arguments with proper escaping, starting the process, and waiting for exit. Error handling requires checking exit codes and parsing standard error output.

IronPDF creates a ChromePdfRenderer, calls RenderHtmlFileAsPdf() with the file path, and saves with SaveAs(). The operation is three lines of code with standard .NET exception handling.

For advanced HTML rendering options, explore the HTML to PDF conversion guide.

HTML String to PDF Conversion

Converting HTML strings shows HTMLDOC's temporary file requirement versus IronPDF's in-memory processing.

HTMLDOC:

// HTMLDOC command-line with string input
using System.Diagnostics;
using System.IO;

class HtmlDocExample
{
    static void Main()
    {
        string htmlContent = "<html><body><h1>Hello World</h1></body></html>";

        // Write HTML to temporary file
        string tempFile = Path.GetTempFileName() + ".html";
        File.WriteAllText(tempFile, htmlContent);

        ProcessStartInfo startInfo = new ProcessStartInfo
        {
            FileName = "htmldoc",
            Arguments = $"--webpage -f output.pdf {tempFile}",
            UseShellExecute = false,
            CreateNoWindow = true
        };

        Process process = Process.Start(startInfo);
        process.WaitForExit();

        File.Delete(tempFile);
    }
}
// HTMLDOC command-line with string input
using System.Diagnostics;
using System.IO;

class HtmlDocExample
{
    static void Main()
    {
        string htmlContent = "<html><body><h1>Hello World</h1></body></html>";

        // Write HTML to temporary file
        string tempFile = Path.GetTempFileName() + ".html";
        File.WriteAllText(tempFile, htmlContent);

        ProcessStartInfo startInfo = new ProcessStartInfo
        {
            FileName = "htmldoc",
            Arguments = $"--webpage -f output.pdf {tempFile}",
            UseShellExecute = false,
            CreateNoWindow = true
        };

        Process process = Process.Start(startInfo);
        process.WaitForExit();

        File.Delete(tempFile);
    }
}
$vbLabelText   $csharpLabel

IronPDF:

// NuGet: Install-Package IronPdf
using IronPdf;

class IronPdfExample
{
    static void Main()
    {
        string htmlContent = "<html><body><h1>Hello World</h1></body></html>";

        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf(htmlContent);
        pdf.SaveAs("output.pdf");
    }
}
// NuGet: Install-Package IronPdf
using IronPdf;

class IronPdfExample
{
    static void Main()
    {
        string htmlContent = "<html><body><h1>Hello World</h1></body></html>";

        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf(htmlContent);
        pdf.SaveAs("output.pdf");
    }
}
$vbLabelText   $csharpLabel

HTMLDOC cannot accept HTML strings directly—it requires writing content to a temporary file first using Path.GetTempFileName() and File.WriteAllText(), then passing the file path as an argument, and finally cleaning up with File.Delete(). This introduces I/O overhead and requires careful cleanup handling, especially in error scenarios.

IronPDF's RenderHtmlAsPdf() method accepts HTML strings directly, processing content in memory without temporary files. This simplifies code, reduces I/O operations, and eliminates cleanup requirements.

URL to PDF with Headers and Footers

Converting URLs with headers and footers demonstrates the configuration approach differences.

HTMLDOC:

// HTMLDOC command-line with URL and headers
using System.Diagnostics;

class HtmlDocExample
{
    static void Main()
    {
        // HTMLDOC has limited support for URLs and headers
        ProcessStartInfo startInfo = new ProcessStartInfo
        {
            FileName = "htmldoc",
            Arguments = "--webpage --header \"Page #\" --footer \"t\" -f output.pdf https://example.com",
            UseShellExecute = false,
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            CreateNoWindow = true
        };

        Process process = Process.Start(startInfo);
        process.WaitForExit();

        // Note: HTMLDOC may not render modern web pages correctly
    }
}
// HTMLDOC command-line with URL and headers
using System.Diagnostics;

class HtmlDocExample
{
    static void Main()
    {
        // HTMLDOC has limited support for URLs and headers
        ProcessStartInfo startInfo = new ProcessStartInfo
        {
            FileName = "htmldoc",
            Arguments = "--webpage --header \"Page #\" --footer \"t\" -f output.pdf https://example.com",
            UseShellExecute = false,
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            CreateNoWindow = true
        };

        Process process = Process.Start(startInfo);
        process.WaitForExit();

        // Note: HTMLDOC may not render modern web pages correctly
    }
}
$vbLabelText   $csharpLabel

IronPDF:

// NuGet: Install-Package IronPdf
using IronPdf;

class IronPdfExample
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();

        renderer.RenderingOptions.TextHeader.CenterText = "Page {page}";
        renderer.RenderingOptions.TextFooter.CenterText = "{date}";

        var pdf = renderer.RenderUrlAsPdf("https://example.com");
        pdf.SaveAs("output.pdf");
    }
}
// NuGet: Install-Package IronPdf
using IronPdf;

class IronPdfExample
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();

        renderer.RenderingOptions.TextHeader.CenterText = "Page {page}";
        renderer.RenderingOptions.TextFooter.CenterText = "{date}";

        var pdf = renderer.RenderUrlAsPdf("https://example.com");
        pdf.SaveAs("output.pdf");
    }
}
$vbLabelText   $csharpLabel

HTMLDOC configures headers and footers through command-line flags (--header, --footer) with limited formatting options. The code notes that HTMLDOC may not render modern web pages correctly due to its outdated HTML parser.

IronPDF uses RenderingOptions.TextHeader and RenderingOptions.TextFooter with properties like CenterText. Placeholders use {page} for page numbers and {date} for dates. The RenderUrlAsPdf() method handles URL rendering with full JavaScript execution via the Chromium engine.

Learn more about header and footer configuration in the IronPDF tutorials.

API Mapping Reference

For developers evaluating HTMLDOC migration or comparing capabilities, this mapping shows equivalent operations:

Command-Line Flag to IronPDF Mapping

HTMLDOC FlagIronPDF Equivalent
--webpage -f output.pdf input.htmlrenderer.RenderHtmlFileAsPdf("input.html").SaveAs("output.pdf")
--size A4RenderingOptions.PaperSize = PdfPaperSize.A4
--size LetterRenderingOptions.PaperSize = PdfPaperSize.Letter
--landscapeRenderingOptions.PaperOrientation = PdfPaperOrientation.Landscape
--portraitRenderingOptions.PaperOrientation = PdfPaperOrientation.Portrait
--top 20mmRenderingOptions.MarginTop = 20
--bottom 20mmRenderingOptions.MarginBottom = 20
--left 20mmRenderingOptions.MarginLeft = 20
--right 20mmRenderingOptions.MarginRight = 20
--header "..."RenderingOptions.TextHeader or HtmlHeader
--footer "..."RenderingOptions.TextFooter or HtmlFooter
--encryptionpdf.SecuritySettings.MakeDocumentReadOnly(password)
--user-password xxxpdf.SecuritySettings.UserPassword
--owner-password xxxpdf.SecuritySettings.OwnerPassword
--embedfontsDefault behavior

Placeholder Syntax Mapping

Header and footer placeholders use different syntax between the tools:

HTMLDOCIronPDF
$PAGE{page}
$PAGES{total-pages}
$DATE{date}
$TIME{time}
$TITLE{html-title}

Feature Comparison Summary

FeatureHTMLDOCIronPDF
HTML5 Support❌ (HTML 3.2)✅
CSS3 Support❌ (Minimal CSS)✅
Flexbox/Grid❌✅
JavaScript Execution❌✅
Native .NET Library❌ (Command-line)✅
NuGet Package❌✅
In-Memory Processing❌ (Requires temp files)✅
Async/Await❌✅
Thread Safety❌✅
Commercial License❌ (GPL viral)✅
Active Development⚠️ Minimal✅
Professional Support❌ (Community only)✅

When Teams Consider Moving from HTMLDOC to IronPDF

Development teams evaluate transitioning from HTMLDOC to IronPDF for several reasons:

Outdated Web Standards: HTMLDOC was built before CSS became integral to web design. It lacks support for CSS3, HTML5, Flexbox, and Grid—all essential for modern web content. Teams finding their HTML templates render incorrectly or require dumbing down for HTMLDOC compatibility often seek modern alternatives.

No JavaScript Support: HTMLDOC cannot execute JavaScript, making dynamic content impossible. Modern web applications frequently rely on JavaScript for data loading, charting, and interactive elements. IronPDF's Chromium engine provides full JavaScript execution.

GPL License Concerns: The GPL license's viral nature requires any incorporating software to also be GPL—problematic for commercial products. Teams developing proprietary software often cannot use GPL-licensed dependencies. IronPDF's commercial license allows integration into proprietary software.

Command-Line Complexity: HTMLDOC requires process spawning, temporary files, output parsing, and shell escaping. This adds code complexity, potential security concerns, and failure points in server environments. IronPDF's native .NET API eliminates these concerns.

Platform Dependencies: HTMLDOC requires the binary installed on the target system, complicating deployment and containerization. IronPDF deploys via NuGet with no external dependencies.

No Async Support: HTMLDOC's synchronous process execution blocks threads. IronPDF provides full async/await support for non-blocking PDF generation in modern .NET applications.

Limited Maintenance: As legacy technology from the 1990s, HTMLDOC receives minimal updates. IronPDF provides active development with regular releases and security patches.

Strengths and Considerations

HTMLDOC Strengths

  • Stability Over Time: Decades of use for straightforward HTML documents
  • Open Source: Available for public modification under GPL
  • Free: No licensing cost for GPL-compliant usage

HTMLDOC Considerations

  • Outdated Technology: Custom HTML parser from 1990s with no modern web support
  • Command-Line Only: No native .NET integration
  • GPL License: Viral license restricts commercial use
  • Temp File Requirement: Cannot process HTML strings directly
  • No JavaScript: Dynamic content impossible
  • Platform Dependencies: Requires external binary installation
  • Minimal Maintenance: Limited updates and community-only support

IronPDF Strengths

  • Modern Chromium Engine: Full HTML5, CSS3, JavaScript support
  • Native .NET Library: Direct API integration without process spawning
  • In-Memory Processing: No temporary files required
  • Async Support: Non-blocking PDF generation
  • Thread Safety: Safe for multi-threaded server environments
  • Commercial License: Deploy in proprietary software
  • Active Support: Regular updates and professional support
  • Comprehensive Resources: Extensive tutorials and documentation

IronPDF Considerations

  • Commercial License: Required for production use

Conclusion

HTMLDOC and IronPDF represent fundamentally different eras of HTML-to-PDF technology. HTMLDOC, dating from the late 1990s, provides command-line conversion using a custom HTML parser that predates modern web standards. The tool requires external binary installation, process spawning, temporary file management, and operates under GPL licensing restrictions.

IronPDF provides a modern alternative with native .NET integration, Chromium-based rendering for full HTML5/CSS3/JavaScript support, in-memory processing without temporary files, and async/await patterns for non-blocking operations. The library deploys via NuGet with no external dependencies.

As organizations plan for .NET 10, C# 14, and application development through 2026, the choice between legacy command-line tools with 1990s rendering and modern native libraries with current web standards significantly impacts both development velocity and output quality. Teams requiring modern web content rendering, native .NET integration, or commercial licensing will find IronPDF addresses these requirements effectively.

Start evaluating IronPDF with a free trial and explore the comprehensive documentation to assess fit for your specific requirements.