PdfPig vs IronPDF: Technical Comparison Guide

What Is PdfPig?

PdfPig is an open-source PDF reading and extraction library specifically designed for C#. It allows developers to access PDF content accurately, providing tools for extracting text, images, form data, and metadata from PDF files. Licensed under the Apache 2.0 License, pdfpig is both open source and business-friendly, allowing modifications and distribution as part of proprietary applications.

While pdfpig excels in extraction capabilities, its scope is limited to parsing existing documents. The library cannot create PDFs from HTML, URLs, or programmatically—it focuses exclusively on reading what already exists.

Key characteristics of pdfpig include:

• Reading-Only Focus: Designed specifically for PDF parsing and extraction
• Open Source: Apache 2.0 license with no licensing costs
• Text Extraction with Position Data: Accurately extracts text with positional data and handles character fonts carefully
• Word-Level Analysis: Provides word bounding boxes for layout analysis
• Pure .NET: No native dependencies, works anywhere .NET runs
• 1-Based Page Indexing: Pages are accessed using 1-based indexing

What Is IronPDF?

IronPDF is a complete .NET library providing full PDF lifecycle management. The ChromePdfRenderer class uses a modern Chromium-based engine for HTML-to-PDF conversion, while the PdfDocument class offers extensive manipulation and extraction capabilities.

Unlike pdfpig's reading-only focus, IronPDF supports both PDF generation and extraction, making it a flexible option for various PDF-related tasks. The library handles creation from HTML and URLs, text extraction, document manipulation, merging, watermarking, security features, and digital signatures—all within a single library.

Architectural Comparison

The main difference between pdfpig and IronPDF lies in their scope: reading-only versus complete PDF lifecycle management.

For applications requiring only PDF reading and text extraction, pdfpig provides excellent capabilities. For applications needing PDF generation, document manipulation, or any creation capabilities, IronPDF provides a complete solution.

Text Extraction Comparison

Text extraction demonstrates both libraries' strengths in this common workflow, with notable differences in API design.

PdfPig text extraction approach:

// NuGet: Install-Package PdfPig
using UglyToad.PdfPig;
using System;
using System.Text;

class Program
{
    static void Main()
    {
        using (var document = PdfDocument.Open("input.pdf"))
        {
            var text = new StringBuilder();
            foreach (var page in document.GetPages())
            {
                text.AppendLine(page.Text);
            }
            Console.WriteLine(text.ToString());
        }
    }
}

// NuGet: Install-Package PdfPig
using UglyToad.PdfPig;
using System;
using System.Text;

class Program
{
    static void Main()
    {
        using (var document = PdfDocument.Open("input.pdf"))
        {
            var text = new StringBuilder();
            foreach (var page in document.GetPages())
            {
                text.AppendLine(page.Text);
            }
            Console.WriteLine(text.ToString());
        }
    }
}

IronPDF text extraction approach:

// NuGet: Install-Package IronPdf
using IronPdf;
using System;

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("input.pdf");
        string text = pdf.ExtractAllText();
        Console.WriteLine(text);
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;
using System;

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("input.pdf");
        string text = pdf.ExtractAllText();
        Console.WriteLine(text);
    }
}

PdfPig requires a using statement for proper disposal, iteration through pages via GetPages(), and manual text aggregation with StringBuilder. The page.Text property provides the text content for each page.

IronPDF's ExtractAllText() method extracts all text from all pages in a single call, without requiring manual iteration or disposal patterns. For page-by-page extraction, IronPDF provides ExtractTextFromPage(index). Note the API difference: pdfpig uses PdfDocument.Open() while IronPDF uses PdfDocument.FromFile().

HTML to PDF Conversion

HTML-to-PDF conversion demonstrates the fundamental capability gap between these libraries.

PdfPig HTML-to-PDF approach:

// PdfPig does not support HTML to PDF conversion
// PdfPig is a PDF reading/parsing library, not a PDF generation library
// You would need to use a different library for HTML to PDF conversion

// PdfPig does not support HTML to PDF conversion
// PdfPig is a PDF reading/parsing library, not a PDF generation library
// You would need to use a different library for HTML to PDF conversion

IronPDF HTML-to-PDF approach:

// NuGet: Install-Package IronPdf
using IronPdf;

class Program
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1><p>This is a PDF from HTML</p>");
        pdf.SaveAs("output.pdf");
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;

class Program
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1><p>This is a PDF from HTML</p>");
        pdf.SaveAs("output.pdf");
    }
}

PdfPig cannot create PDFs from HTML—it simply doesn't support this functionality. The library is designed exclusively for reading and parsing existing PDF documents, not generating new ones.

IronPDF's ChromePdfRenderer uses a modern Chromium engine to convert HTML content with full support for CSS3 and JavaScript, producing high-fidelity PDF output from web content. For detailed guidance on HTML-to-PDF conversion patterns, see the HTML to PDF tutorial.

PDF Metadata Access

Reading PDF metadata shows similar capabilities with different API patterns.

PdfPig metadata reading:

// NuGet: Install-Package PdfPig
using UglyToad.PdfPig;
using System;

class Program
{
    static void Main()
    {
        using (var document = PdfDocument.Open("input.pdf"))
        {
            var info = document.Information;
            Console.WriteLine($"Title: {info.Title}");
            Console.WriteLine($"Author: {info.Author}");
            Console.WriteLine($"Subject: {info.Subject}");
            Console.WriteLine($"Creator: {info.Creator}");
            Console.WriteLine($"Producer: {info.Producer}");
            Console.WriteLine($"Number of Pages: {document.NumberOfPages}");
        }
    }
}

// NuGet: Install-Package PdfPig
using UglyToad.PdfPig;
using System;

class Program
{
    static void Main()
    {
        using (var document = PdfDocument.Open("input.pdf"))
        {
            var info = document.Information;
            Console.WriteLine($"Title: {info.Title}");
            Console.WriteLine($"Author: {info.Author}");
            Console.WriteLine($"Subject: {info.Subject}");
            Console.WriteLine($"Creator: {info.Creator}");
            Console.WriteLine($"Producer: {info.Producer}");
            Console.WriteLine($"Number of Pages: {document.NumberOfPages}");
        }
    }
}

IronPDF metadata reading:

// NuGet: Install-Package IronPdf
using IronPdf;
using System;

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("input.pdf");
        var info = pdf.MetaData;
        Console.WriteLine($"Title: {info.Title}");
        Console.WriteLine($"Author: {info.Author}");
        Console.WriteLine($"Subject: {info.Subject}");
        Console.WriteLine($"Creator: {info.Creator}");
        Console.WriteLine($"Producer: {info.Producer}");
        Console.WriteLine($"Number of Pages: {pdf.PageCount}");
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;
using System;

class Program
{
    static void Main()
    {
        var pdf = PdfDocument.FromFile("input.pdf");
        var info = pdf.MetaData;
        Console.WriteLine($"Title: {info.Title}");
        Console.WriteLine($"Author: {info.Author}");
        Console.WriteLine($"Subject: {info.Subject}");
        Console.WriteLine($"Creator: {info.Creator}");
        Console.WriteLine($"Producer: {info.Producer}");
        Console.WriteLine($"Number of Pages: {pdf.PageCount}");
    }
}

Both libraries provide access to standard PDF metadata properties. PdfPig uses document.Information while IronPDF uses pdf.MetaData. Page count is accessed via document.NumberOfPages in pdfpig versus pdf.PageCount in IronPDF.

API Mapping Reference

For teams evaluating pdfpig migration to IronPDF, understanding the API mappings helps estimate development effort.

Page Indexing Difference

A critical difference for migration: pdfpig uses 1-based page indexing while IronPDF uses 0-based indexing.

PdfPig page access:

// PdfPig: 1-based indexing
var firstPage = document.GetPage(1);  // First page
var secondPage = document.GetPage(2); // Second page

// PdfPig: 1-based indexing
var firstPage = document.GetPage(1);  // First page
var secondPage = document.GetPage(2); // Second page

IronPDF page access:

// IronPDF: 0-based indexing
var firstPage = pdf.Pages[0];  // First page
var secondPage = pdf.Pages[1]; // Second page

// IronPDF: 0-based indexing
var firstPage = pdf.Pages[0];  // First page
var secondPage = pdf.Pages[1]; // Second page

This difference requires careful attention when migrating code that references specific pages.

Word Position Data

One area where pdfpig has a distinct advantage is providing word-level position data.

PdfPig word positions:

using (var document = PdfDocument.Open("input.pdf"))
{
    foreach (var page in document.GetPages())
    {
        var words = page.GetWords();
        foreach (var word in words)
        {
            // PdfPig provides bounding box coordinates
            Console.WriteLine($"Word: '{word.Text}' at ({word.BoundingBox.Left}, {word.BoundingBox.Top})");
        }
    }
}

using (var document = PdfDocument.Open("input.pdf"))
{
    foreach (var page in document.GetPages())
    {
        var words = page.GetWords();
        foreach (var word in words)
        {
            // PdfPig provides bounding box coordinates
            Console.WriteLine($"Word: '{word.Text}' at ({word.BoundingBox.Left}, {word.BoundingBox.Top})");
        }
    }
}

PdfPig's word.BoundingBox provides precise positioning data for each word, enabling layout analysis, table detection, and document structure understanding. IronPDF extracts text without position data—if word-level coordinates are essential, consider a hybrid approach using both libraries.

Disposal Pattern Differences

The libraries differ in their memory management requirements.

PdfPig disposal (required):

// PdfPig requires using statement for proper disposal
using (var document = PdfDocument.Open("input.pdf"))
{
    // Work with document
}

// PdfPig requires using statement for proper disposal
using (var document = PdfDocument.Open("input.pdf"))
{
    // Work with document
}

IronPDF disposal (optional):

// IronPDF doesn't require using statement
var pdf = PdfDocument.FromFile("input.pdf");
// Work with pdf
// Dispose optional: pdf.Dispose();

// IronPDF doesn't require using statement
var pdf = PdfDocument.FromFile("input.pdf");
// Work with pdf
// Dispose optional: pdf.Dispose();

PdfPig requires the using pattern for proper resource cleanup. IronPDF's PdfDocument doesn't require explicit disposal, though it can be disposed if needed.

Feature Comparison Summary

The scope difference between pdfpig and IronPDF spans virtually every PDF operation beyond reading.

Applications requiring watermarking, PDF merging, or security features cannot achieve these with pdfpig alone.

When Teams Consider Moving from PdfPig to IronPDF

Several factors drive teams to evaluate IronPDF as an alternative or complement to pdfpig:

PDF Creation Requirements: PdfPig cannot create PDFs from HTML, URLs, or programmatically. Applications needing to generate PDFs from web content or templates require additional libraries—or IronPDF's complete solution.

Document Manipulation Needs: PdfPig cannot merge, split, or modify PDFs. Applications requiring document assembly or modification need IronPDF's manipulation capabilities.

Security Requirements: PdfPig cannot add passwords, encryption, or digital signatures. Applications with security requirements need IronPDF's security features.

Watermarking and Branding: PdfPig cannot add visual overlays to existing documents. Applications requiring document branding need IronPDF's watermarking capabilities.

Professional Support: PdfPig relies on community support. Organizations requiring guaranteed response times and professional assistance benefit from IronPDF's commercial support.

Hybrid Approach: Some teams use both libraries—pdfpig for detailed text analysis with word positions, and IronPDF for generation and manipulation. This approach leverages each library's strengths.

Installation Comparison

PdfPig installation:

Install-Package PdfPig

Install-Package PdfPig

Pure .NET with no native dependencies.

IronPDF installation:

Install-Package IronPdf

Install-Package IronPdf

IronPDF requires a license key configuration:

IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

IronPDF's first run downloads the Chromium rendering engine (~150MB one-time). For Linux deployments, additional dependencies are required. The library supports .NET Framework, .NET Core, .NET 5+, and forward compatibility into .NET 10 and C# 14.

Making the Decision

The choice between pdfpig and IronPDF depends on your application requirements:

Consider PdfPig if: Your primary need is solid extraction and reading capabilities, you require word-level position data for layout analysis, you want a cost-effective solution with an open-source license, and you don't need PDF generation or manipulation.

Consider IronPDF if: You need comprehensive PDF lifecycle support including HTML to PDF conversion, your project necessitates PDF creation and editing features, you require document manipulation (merge, split, watermark), you need security features (passwords, encryption, signatures), or you require professional support backed by commercial licensing.

Consider Both: For advanced text analysis with PDF generation, a hybrid approach leverages pdfpig's word position capabilities with IronPDF's creation and manipulation features.

Getting Started with IronPDF

To evaluate IronPDF for your PDF needs:

1. Install via NuGet: Install-Package IronPdf
2. Review the getting started documentation
3. Explore HTML to PDF tutorials for creation patterns
4. Check the API reference for complete method documentation

The IronPDF tutorials provide comprehensive examples covering common scenarios from basic conversion to advanced PDF manipulation.

PdfPig and IronPDF serve fundamentally different purposes in the .NET PDF ecosystem. PdfPig excels at PDF reading and text extraction—parsing documents with precision and providing word-level position data for layout analysis. IronPDF provides a complete PDF solution covering creation, extraction, manipulation, and security in a single library.

For applications requiring only PDF reading, pdfpig's focused approach with open-source licensing may be appropriate. For applications needing PDF generation, document manipulation, or any creation capabilities beyond reading, IronPDF provides these features natively without requiring additional libraries.

The decision extends beyond current requirements to anticipated needs. While pdfpig excels in its domain of reading and extraction, IronPDF towers in versatility and comprehensive PDF management. Organizations often start with reading requirements but expand to need generation and manipulation—choosing IronPDF from the start provides a foundation for these expanded requirements while ensuring professional support and active development.

Evaluate your complete PDF requirements—current and anticipated—when selecting between these libraries. The reading-only nature of pdfpig creates capability boundaries that become apparent as applications mature and requirements expand.