The C# PDF Library

HTML to PDF

using IronPdf;

// Disable local disk access or cross-origin requests
Installation.EnableWebSecurity = true;

// Instantiate Renderer
var renderer = new ChromePdfRenderer();

// Create a PDF from a HTML string using C#
var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");

// Export to a file or Stream
pdf.SaveAs("output.pdf");

// Advanced Example with HTML Assets
// Load external html assets: Images, CSS and JavaScript.
// An optional BasePath 'C:\site\assets\' is set as the file location to load assets from
var myAdvancedPdf = renderer.RenderHtmlAsPdf("<img src='icons/iron.png'>", @"C:\site\assets\");
myAdvancedPdf.SaveAs("html-with-assets.pdf");

using IronPdf;

// Disable local disk access or cross-origin requests
Installation.EnableWebSecurity = true;

// Instantiate Renderer
var renderer = new ChromePdfRenderer();

// Create a PDF from a HTML string using C#
var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");

// Export to a file or Stream
pdf.SaveAs("output.pdf");

// Advanced Example with HTML Assets
// Load external html assets: Images, CSS and JavaScript.
// An optional BasePath 'C:\site\assets\' is set as the file location to load assets from
var myAdvancedPdf = renderer.RenderHtmlAsPdf("<img src='icons/iron.png'>", @"C:\site\assets\");
myAdvancedPdf.SaveAs("html-with-assets.pdf");

PM >Install-Package IronPdf

Install-Package IronPdf

MIGRATION GUIDES

How to Migrate from iText to IronPDF in C#

Curtis Chau

Updated: August 1, 2026

Migrating from iText to IronPDF moves your .NET PDF workflow from a programmatic API - building Paragraph, Table, and Cell objects in code - to an HTML-first approach with CSS3 and JavaScript support. This guide provides a step-by-step migration path that removes AGPL exposure and the need for a separate pdfHTML add-on.

Why Migrate from iText to IronPDF

The AGPL License Consideration

iText (owned by iText Group / Apryse Group NV) carries licensing characteristics commercial teams should weigh up front:

AGPL Viral License: If you use iText under its open-source license in a web application, the AGPL is typically interpreted as requiring you to release your application's source to anyone who interacts with it over a network. For closed-source commercial software this usually means buying a commercial license instead.
Subscription-Only Commercial Licensing: iText's commercial license is sold as an annual subscription based on PDF processing volume; a perpetual option is not advertised on the public pricing page (custom OEM terms are quote-only).
pdfHTML Add-On Cost: HTML-to-PDF requires the itext.pdfhtml add-on (currently 6.3.2), sold separately on top of the core itext package (currently 9.6.0).
Complex Licensing Audits: Enterprise deployments face licensing complexity and audit risk.
Programmatic-First API: Core iText builds PDFs by composing Paragraph, Table, and Cell objects in code; pdfHTML lets you start from HTML.
Defined CSS Subset, No JS at Render Time: pdfHTML supports a defined subset of CSS and does not execute JavaScript while converting HTML to PDF (PDF-level JS form actions are a separate, supported feature).

iText vs IronPDF Comparison

Feature	iText 9 / iTextSharp 5.x	IronPDF
License	AGPL (viral) or commercial annual subscription	Commercial, perpetual option
HTML-to-PDF	Separate `itext.pdfhtml` add-on (6.3.2)	Built-in Chromium renderer
CSS Support	Defined CSS subset in pdfHTML	Full CSS3, Flexbox, Grid
JavaScript at render	pdfHTML does not run JS during HTML→PDF	Full JS execution at render time
API Paradigm	Programmatic (Paragraph, Table, Cell)	HTML-first with CSS
Learning Curve	Steep (PDF coordinate system)	Web developer friendly
Open Source Risk	Must open-source web apps under AGPL	No viral requirements
Pricing Model	Annual subscription (volume-based) or custom OEM	Perpetual or subscription

For teams standardising on modern .NET, IronPDF's HTML-first approach leans on web development skills the team already has.

Migration Complexity Assessment

Estimated Effort by Feature

Feature	Migration Complexity
HTML to PDF	Very Low
Merge PDFs	Low
Text and Images	Low
Tables	Medium
Headers/Footers	Medium
Security/Encryption	Low

Paradigm Shift

The fundamental shift in this iText migration is from programmatic PDF construction to HTML-first rendering:

iText:    PdfWriter → PdfDocument → Document → Add(Paragraph) → Add(Table)
IronPDF:  ChromePdfRenderer → RenderHtmlAsPdf(htmlString) → SaveAs()

iText:    PdfWriter → PdfDocument → Document → Add(Paragraph) → Add(Table)
IronPDF:  ChromePdfRenderer → RenderHtmlAsPdf(htmlString) → SaveAs()

Text

This paradigm shift is liberating: instead of learning iText's object model, you use HTML and CSS skills that web developers already possess.

Before You Start

Prerequisites

.NET Environment: .NET Framework 4.6.2+ or .NET Core 3.1+ / .NET 5/6/7/8/9+
NuGet Access: Ability to install NuGet packages
IronPDF License: Obtain your license key from ironpdf.com

NuGet Package Changes

# Remove iText packages (current naming is 'itext'; 'itext7' is the deprecated alias)
dotnet remove package itext
dotnet remove package itext.pdfhtml
dotnet remove package itext7
dotnet remove package itext7.pdfhtml
dotnet remove package itextsharp

# Install IronPDF
dotnet add package IronPdf

# Remove iText packages (current naming is 'itext'; 'itext7' is the deprecated alias)
dotnet remove package itext
dotnet remove package itext.pdfhtml
dotnet remove package itext7
dotnet remove package itext7.pdfhtml
dotnet remove package itextsharp

# Install IronPDF
dotnet add package IronPdf

SHELL

License Configuration

// Add at application startup (Program.cs or Startup.cs)
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

// Add at application startup (Program.cs or Startup.cs)
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY";

' Add at application startup (Program.vb or Startup.vb)
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

' Add at application startup (Program.vb or Startup.vb)
IronPdf.License.LicenseKey = "YOUR-LICENSE-KEY"

Identify iText Usage

# Find all iText references
grep -r "using iText\|using iTextSharp" --include="*.cs" .
grep -r "PdfWriter\|PdfDocument\|Document\|Paragraph\|Table\|Cell" --include="*.cs" .
grep -r "HtmlConverter\|ConverterProperties" --include="*.cs" .

# Find all iText references
grep -r "using iText\|using iTextSharp" --include="*.cs" .
grep -r "PdfWriter\|PdfDocument\|Document\|Paragraph\|Table\|Cell" --include="*.cs" .
grep -r "HtmlConverter\|ConverterProperties" --include="*.cs" .

SHELL

Complete API Reference

Class Mappings

iText 7+ Class	iTextSharp 5.x Class	IronPDF Equivalent
`PdfWriter`	`PdfWriter`	`ChromePdfRenderer`
`PdfDocument`	`Document`	`PdfDocument`
`Document`	`Document`	`ChromePdfRenderer.RenderHtmlAsPdf()`
`Paragraph`	`Paragraph`	HTML `<p>`, `<h1>`, etc.
`Table`	`PdfPTable`	HTML `<table>`
`Cell`	`PdfPCell`	HTML `<td>`, `<th>`
`Image`	`Image`	HTML `<img>`
`PdfReader`	`PdfReader`	`PdfDocument.FromFile()`
`PdfMerger`	N/A	`PdfDocument.Merge()`

Namespace Mappings

iText Namespace	IronPDF Equivalent
`iText.Kernel.Pdf`	`IronPdf`
`iText.Layout`	`IronPdf`
`iText.Layout.Element`	Use HTML elements
`iText.Html2pdf`	`IronPdf` (built-in)
`iText.IO.Image`	Use HTML `<img>`
`iText.Kernel.Utils`	`IronPdf`

Code Migration Examples

Example 1: HTML to PDF Conversion

Before (iText):

// NuGet: Install-Package itext7
using iText.Html2pdf;
using System.IO;

class Program
{
    static void Main()
    {
        string html = "<h1>Hello World</h1><p>This is a PDF from HTML.</p>";
        string outputPath = "output.pdf";
        
        using (FileStream fs = new FileStream(outputPath, FileMode.Create))
        {
            HtmlConverter.ConvertToPdf(html, fs);
        }
    }
}

// NuGet: Install-Package itext7
using iText.Html2pdf;
using System.IO;

class Program
{
    static void Main()
    {
        string html = "<h1>Hello World</h1><p>This is a PDF from HTML.</p>";
        string outputPath = "output.pdf";
        
        using (FileStream fs = new FileStream(outputPath, FileMode.Create))
        {
            HtmlConverter.ConvertToPdf(html, fs);
        }
    }
}

' NuGet: Install-Package itext7
Imports iText.Html2pdf
Imports System.IO

Class Program
    Shared Sub Main()
        Dim html As String = "<h1>Hello World</h1><p>This is a PDF from HTML.</p>"
        Dim outputPath As String = "output.pdf"

        Using fs As New FileStream(outputPath, FileMode.Create)
            HtmlConverter.ConvertToPdf(html, fs)
        End Using
    End Sub
End Class

' NuGet: Install-Package itext7
Imports iText.Html2pdf
Imports System.IO

Class Program
    Shared Sub Main()
        Dim html As String = "<h1>Hello World</h1><p>This is a PDF from HTML.</p>"
        Dim outputPath As String = "output.pdf"

        Using fs As New FileStream(outputPath, FileMode.Create)
            HtmlConverter.ConvertToPdf(html, fs)
        End Using
    End Sub
End Class

After (IronPDF):

// NuGet: Install-Package IronPdf
using IronPdf;

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

// NuGet: Install-Package IronPdf
using IronPdf;

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

' NuGet: Install-Package IronPdf
Imports IronPdf

Class Program
    Shared Sub Main()
        Dim renderer = New ChromePdfRenderer()
        Dim html As String = "<h1>Hello World</h1><p>This is a PDF from HTML.</p>"

        Dim pdf = renderer.RenderHtmlAsPdf(html)
        pdf.SaveAs("output.pdf")
    End Sub
End Class

' NuGet: Install-Package IronPdf
Imports IronPdf

Class Program
    Shared Sub Main()
        Dim renderer = New ChromePdfRenderer()
        Dim html As String = "<h1>Hello World</h1><p>This is a PDF from HTML.</p>"

        Dim pdf = renderer.RenderHtmlAsPdf(html)
        pdf.SaveAs("output.pdf")
    End Sub
End Class

The iText approach requires the separate itext.pdfhtml package (pdfHTML add-on, currently 6.3.2, sold separately on top of itext 9.6.0), creating a FileStream, and wrapping everything in using statements for proper disposal. The HtmlConverter.ConvertToPdf() method writes directly to the stream.

IronPDF's approach is cleaner: create a ChromePdfRenderer, call RenderHtmlAsPdf() with your HTML string, and call SaveAs() on the resulting PdfDocument. No separate packages, no stream management, and the Chromium rendering engine provides superior CSS3 and JavaScript support. See the HTML to PDF documentation for additional rendering options.

Example 2: Merge Multiple PDFs

Before (iText):

// NuGet: Install-Package itext7
using iText.Kernel.Pdf;
using iText.Kernel.Utils;
using System.IO;

class Program
{
    static void Main()
    {
        string outputPath = "merged.pdf";
        string[] inputFiles = { "document1.pdf", "document2.pdf", "document3.pdf" };
        
        using (PdfWriter writer = new PdfWriter(outputPath))
        using (PdfDocument pdfDoc = new PdfDocument(writer))
        {
            PdfMerger merger = new PdfMerger(pdfDoc);
            
            foreach (string file in inputFiles)
            {
                using (PdfDocument sourcePdf = new PdfDocument(new PdfReader(file)))
                {
                    merger.Merge(sourcePdf, 1, sourcePdf.GetNumberOfPages());
                }
            }
        }
    }
}

// NuGet: Install-Package itext7
using iText.Kernel.Pdf;
using iText.Kernel.Utils;
using System.IO;

class Program
{
    static void Main()
    {
        string outputPath = "merged.pdf";
        string[] inputFiles = { "document1.pdf", "document2.pdf", "document3.pdf" };
        
        using (PdfWriter writer = new PdfWriter(outputPath))
        using (PdfDocument pdfDoc = new PdfDocument(writer))
        {
            PdfMerger merger = new PdfMerger(pdfDoc);
            
            foreach (string file in inputFiles)
            {
                using (PdfDocument sourcePdf = new PdfDocument(new PdfReader(file)))
                {
                    merger.Merge(sourcePdf, 1, sourcePdf.GetNumberOfPages());
                }
            }
        }
    }
}

' NuGet: Install-Package itext7
Imports iText.Kernel.Pdf
Imports iText.Kernel.Utils
Imports System.IO

Class Program
    Shared Sub Main()
        Dim outputPath As String = "merged.pdf"
        Dim inputFiles As String() = {"document1.pdf", "document2.pdf", "document3.pdf"}
        
        Using writer As New PdfWriter(outputPath),
              pdfDoc As New PdfDocument(writer)
            
            Dim merger As New PdfMerger(pdfDoc)
            
            For Each file As String In inputFiles
                Using sourcePdf As New PdfDocument(New PdfReader(file))
                    merger.Merge(sourcePdf, 1, sourcePdf.GetNumberOfPages())
                End Using
            Next
        End Using
    End Sub
End Class

' NuGet: Install-Package itext7
Imports iText.Kernel.Pdf
Imports iText.Kernel.Utils
Imports System.IO

Class Program
    Shared Sub Main()
        Dim outputPath As String = "merged.pdf"
        Dim inputFiles As String() = {"document1.pdf", "document2.pdf", "document3.pdf"}
        
        Using writer As New PdfWriter(outputPath),
              pdfDoc As New PdfDocument(writer)
            
            Dim merger As New PdfMerger(pdfDoc)
            
            For Each file As String In inputFiles
                Using sourcePdf As New PdfDocument(New PdfReader(file))
                    merger.Merge(sourcePdf, 1, sourcePdf.GetNumberOfPages())
                End Using
            Next
        End Using
    End Sub
End Class

After (IronPDF):

// NuGet: Install-Package IronPdf
using IronPdf;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        var pdfDocuments = new List<PdfDocument>
        {
            PdfDocument.FromFile("document1.pdf"),
            PdfDocument.FromFile("document2.pdf"),
            PdfDocument.FromFile("document3.pdf")
        };
        
        var merged = PdfDocument.Merge(pdfDocuments);
        merged.SaveAs("merged.pdf");
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        var pdfDocuments = new List<PdfDocument>
        {
            PdfDocument.FromFile("document1.pdf"),
            PdfDocument.FromFile("document2.pdf"),
            PdfDocument.FromFile("document3.pdf")
        };
        
        var merged = PdfDocument.Merge(pdfDocuments);
        merged.SaveAs("merged.pdf");
    }
}

' NuGet: Install-Package IronPdf
Imports IronPdf
Imports System.Collections.Generic

Module Program
    Sub Main()
        Dim pdfDocuments As New List(Of PdfDocument) From {
            PdfDocument.FromFile("document1.pdf"),
            PdfDocument.FromFile("document2.pdf"),
            PdfDocument.FromFile("document3.pdf")
        }
        
        Dim merged = PdfDocument.Merge(pdfDocuments)
        merged.SaveAs("merged.pdf")
    End Sub
End Module

' NuGet: Install-Package IronPdf
Imports IronPdf
Imports System.Collections.Generic

Module Program
    Sub Main()
        Dim pdfDocuments As New List(Of PdfDocument) From {
            PdfDocument.FromFile("document1.pdf"),
            PdfDocument.FromFile("document2.pdf"),
            PdfDocument.FromFile("document3.pdf")
        }
        
        Dim merged = PdfDocument.Merge(pdfDocuments)
        merged.SaveAs("merged.pdf")
    End Sub
End Module

The iText merge operation requires significant boilerplate: creating a PdfWriter for output, wrapping it in a PdfDocument, creating a PdfMerger, then iterating through source files with nested using statements for each PdfDocument and PdfReader. You must also specify page ranges with merger.Merge(sourcePdf, 1, sourcePdf.GetNumberOfPages()).

IronPDF reduces this to three steps: load documents with PdfDocument.FromFile(), call the static PdfDocument.Merge() method with the list, and save. The entire merge operation becomes readable and maintainable. Learn more about merging and splitting PDFs.

Example 3: Create PDF with Text and Images

Before (iText):

// NuGet: Install-Package itext7
using iText.Kernel.Pdf;
using iText.Layout;
using iText.Layout.Element;
using iText.IO.Image;

class Program
{
    static void Main()
    {
        string outputPath = "document.pdf";
        
        using (PdfWriter writer = new PdfWriter(outputPath))
        using (PdfDocument pdf = new PdfDocument(writer))
        using (Document document = new Document(pdf))
        {
            document.Add(new Paragraph("Sample PDF Document"));
            document.Add(new Paragraph("This document contains text and an image."));
            
            Image img = new Image(ImageDataFactory.Create("image.jpg"));
            img.SetWidth(200);
            document.Add(img);
        }
    }
}

// NuGet: Install-Package itext7
using iText.Kernel.Pdf;
using iText.Layout;
using iText.Layout.Element;
using iText.IO.Image;

class Program
{
    static void Main()
    {
        string outputPath = "document.pdf";
        
        using (PdfWriter writer = new PdfWriter(outputPath))
        using (PdfDocument pdf = new PdfDocument(writer))
        using (Document document = new Document(pdf))
        {
            document.Add(new Paragraph("Sample PDF Document"));
            document.Add(new Paragraph("This document contains text and an image."));
            
            Image img = new Image(ImageDataFactory.Create("image.jpg"));
            img.SetWidth(200);
            document.Add(img);
        }
    }
}

' NuGet: Install-Package itext7
Imports iText.Kernel.Pdf
Imports iText.Layout
Imports iText.Layout.Element
Imports iText.IO.Image

Module Program
    Sub Main()
        Dim outputPath As String = "document.pdf"

        Using writer As New PdfWriter(outputPath),
              pdf As New PdfDocument(writer),
              document As New Document(pdf)

            document.Add(New Paragraph("Sample PDF Document"))
            document.Add(New Paragraph("This document contains text and an image."))

            Dim img As New Image(ImageDataFactory.Create("image.jpg"))
            img.SetWidth(200)
            document.Add(img)
        End Using
    End Sub
End Module

' NuGet: Install-Package itext7
Imports iText.Kernel.Pdf
Imports iText.Layout
Imports iText.Layout.Element
Imports iText.IO.Image

Module Program
    Sub Main()
        Dim outputPath As String = "document.pdf"

        Using writer As New PdfWriter(outputPath),
              pdf As New PdfDocument(writer),
              document As New Document(pdf)

            document.Add(New Paragraph("Sample PDF Document"))
            document.Add(New Paragraph("This document contains text and an image."))

            Dim img As New Image(ImageDataFactory.Create("image.jpg"))
            img.SetWidth(200)
            document.Add(img)
        End Using
    End Sub
End Module

After (IronPDF):

// NuGet: Install-Package IronPdf
using IronPdf;

class Program
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();
        
        string html = @"
            <h1>Sample PDF Document</h1>
            <p>This document contains text and an image.</p>
            <img src='image.jpg' width='200' />";
        
        var pdf = renderer.RenderHtmlAsPdf(html);
        pdf.SaveAs("document.pdf");
    }
}

// NuGet: Install-Package IronPdf
using IronPdf;

class Program
{
    static void Main()
    {
        var renderer = new ChromePdfRenderer();
        
        string html = @"
            <h1>Sample PDF Document</h1>
            <p>This document contains text and an image.</p>
            <img src='image.jpg' width='200' />";
        
        var pdf = renderer.RenderHtmlAsPdf(html);
        pdf.SaveAs("document.pdf");
    }
}

' NuGet: Install-Package IronPdf
Imports IronPdf

Module Program
    Sub Main()
        Dim renderer = New ChromePdfRenderer()

        Dim html As String = "
            <h1>Sample PDF Document</h1>
            <p>This document contains text and an image.</p>
            <img src='image.jpg' width='200' />"

        Dim pdf = renderer.RenderHtmlAsPdf(html)
        pdf.SaveAs("document.pdf")
    End Sub
End Module

' NuGet: Install-Package IronPdf
Imports IronPdf

Module Program
    Sub Main()
        Dim renderer = New ChromePdfRenderer()

        Dim html As String = "
            <h1>Sample PDF Document</h1>
            <p>This document contains text and an image.</p>
            <img src='image.jpg' width='200' />"

        Dim pdf = renderer.RenderHtmlAsPdf(html)
        pdf.SaveAs("document.pdf")
    End Sub
End Module

This example illustrates the paradigm shift most clearly. iText requires:

Triple-nested using statements (PdfWriter, PdfDocument, Document)
Creating Paragraph objects for each text element with new Paragraph()
Using ImageDataFactory.Create() to load images
Creating an Image object and calling SetWidth() separately
Calling document.Add() for each element

IronPDF uses standard HTML: <h1> for headings, <p> for paragraphs, and <img> for images with a width attribute. Web developers can leverage their existing skills immediately, and designers can style documents using CSS they already know.

Critical Migration Notes

Paradigm Shift: Programmatic to HTML-First

The most significant change in this iText migration is conceptual. iText builds PDFs programmatically:

// iText approach
document.Add(new Paragraph("Title")
    .SetTextAlignment(TextAlignment.CENTER)
    .SetFontSize(24)
    .SetBold());

var table = new Table(UnitValue.CreatePercentArray(3)).UseAllAvailableWidth();
table.AddHeaderCell(new Cell().Add(new Paragraph("ID")));
table.AddHeaderCell(new Cell().Add(new Paragraph("Name")));
// ... many more lines

// iText approach
document.Add(new Paragraph("Title")
    .SetTextAlignment(TextAlignment.CENTER)
    .SetFontSize(24)
    .SetBold());

var table = new Table(UnitValue.CreatePercentArray(3)).UseAllAvailableWidth();
table.AddHeaderCell(new Cell().Add(new Paragraph("ID")));
table.AddHeaderCell(new Cell().Add(new Paragraph("Name")));
// ... many more lines

' iText approach
document.Add(New Paragraph("Title") _
    .SetTextAlignment(TextAlignment.CENTER) _
    .SetFontSize(24) _
    .SetBold())

Dim table = New Table(UnitValue.CreatePercentArray(3)).UseAllAvailableWidth()
table.AddHeaderCell(New Cell().Add(New Paragraph("ID")))
table.AddHeaderCell(New Cell().Add(New Paragraph("Name")))
' ... many more lines

' iText approach
document.Add(New Paragraph("Title") _
    .SetTextAlignment(TextAlignment.CENTER) _
    .SetFontSize(24) _
    .SetBold())

Dim table = New Table(UnitValue.CreatePercentArray(3)).UseAllAvailableWidth()
table.AddHeaderCell(New Cell().Add(New Paragraph("ID")))
table.AddHeaderCell(New Cell().Add(New Paragraph("Name")))
' ... many more lines

IronPDF uses HTML and CSS:

// IronPDF approach
string html = @"
    <style>
        h1 { text-align: center; font-size: 24px; font-weight: bold; }
        table { width: 100%; border-collapse: collapse; }
        th { background-color: #4CAF50; color: white; padding: 8px; }
    </style>
    <h1>Title</h1>
    <table>
        <tr><th>ID</th><th>Name</th></tr>
    </table>";

var pdf = renderer.RenderHtmlAsPdf(html);

// IronPDF approach
string html = @"
    <style>
        h1 { text-align: center; font-size: 24px; font-weight: bold; }
        table { width: 100%; border-collapse: collapse; }
        th { background-color: #4CAF50; color: white; padding: 8px; }
    </style>
    <h1>Title</h1>
    <table>
        <tr><th>ID</th><th>Name</th></tr>
    </table>";

var pdf = renderer.RenderHtmlAsPdf(html);

' IronPDF approach
Dim html As String = "
    <style>
        h1 { text-align: center; font-size: 24px; font-weight: bold; }
        table { width: 100%; border-collapse: collapse; }
        th { background-color: #4CAF50; color: white; padding: 8px; }
    </style>
    <h1>Title</h1>
    <table>
        <tr><th>ID</th><th>Name</th></tr>
    </table>"

Dim pdf = renderer.RenderHtmlAsPdf(html)

' IronPDF approach
Dim html As String = "
    <style>
        h1 { text-align: center; font-size: 24px; font-weight: bold; }
        table { width: 100%; border-collapse: collapse; }
        th { background-color: #4CAF50; color: white; padding: 8px; }
    </style>
    <h1>Title</h1>
    <table>
        <tr><th>ID</th><th>Name</th></tr>
    </table>"

Dim pdf = renderer.RenderHtmlAsPdf(html)

AGPL Exposure Removed

Under iText's AGPL terms, a web application that uses iText is typically expected to release its source to anyone who interacts with it over a network; the commercial license is the alternative path. IronPDF's commercial license allows deployment in proprietary software without viral licensing requirements.

No pdfHTML Add-On Required

iText requires the separate itext.pdfhtml add-on (currently 6.3.2) for HTML-to-PDF conversion, sold on top of the core itext package. IronPDF includes Chromium-based HTML rendering in the base package.

Method Replacement Patterns

iText Pattern	IronPDF Replacement
`SetTextAlignment(TextAlignment.CENTER)`	CSS `text-align: center`
`SetFontSize(24)`	CSS `font-size: 24px`
`SetBold()`	CSS `font-weight: bold`
`new Table(3)`	HTML `<table>`
`AddHeaderCell(new Cell().Add(new Paragraph()))`	HTML `<th>`
`AddCell(new Cell().Add(new Paragraph()))`	HTML `<td>`

Troubleshooting

Issue 1: PdfWriter/Document Pattern

Problem: Code uses the PdfWriter → PdfDocument → Document nesting pattern.

Solution: Replace with ChromePdfRenderer:

// Delete this iText pattern:
// using (var writer = new PdfWriter(outputPath))
// using (var pdfDoc = new PdfDocument(writer))
// using (var document = new Document(pdfDoc))

// Replace with:
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs(outputPath);

// Delete this iText pattern:
// using (var writer = new PdfWriter(outputPath))
// using (var pdfDoc = new PdfDocument(writer))
// using (var document = new Document(pdfDoc))

// Replace with:
var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs(outputPath);

Imports IronPdf

Dim renderer As New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf(html)
pdf.SaveAs(outputPath)

Imports IronPdf

Dim renderer As New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf(html)
pdf.SaveAs(outputPath)

Issue 2: HtmlConverter Not Found

Problem: Code uses iText.Html2pdf.HtmlConverter, which lives in the separately-purchased itext.pdfhtml add-on.

Solution: Use IronPDF's built-in HTML rendering:

// iText (requires pdfHTML add-on)
HtmlConverter.ConvertToPdf(html, fileStream);

// IronPDF (built-in)
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs(outputPath);

// iText (requires pdfHTML add-on)
HtmlConverter.ConvertToPdf(html, fileStream);

// IronPDF (built-in)
var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs(outputPath);

' iText (requires pdfHTML add-on)
HtmlConverter.ConvertToPdf(html, fileStream)

' IronPDF (built-in)
Dim pdf = renderer.RenderHtmlAsPdf(html)
pdf.SaveAs(outputPath)

' iText (requires pdfHTML add-on)
HtmlConverter.ConvertToPdf(html, fileStream)

' IronPDF (built-in)
Dim pdf = renderer.RenderHtmlAsPdf(html)
pdf.SaveAs(outputPath)

Issue 3: PdfMerger Complexity

Problem: iText's PdfMerger requires nested readers and page range specification.

Solution: Use IronPDF's static merge method:

// iText merger pattern (delete this)
// using (PdfDocument pdfDoc = new PdfDocument(writer))
// {
//     PdfMerger merger = new PdfMerger(pdfDoc);
//     foreach (string file in inputFiles)
//     {
//         using (PdfDocument sourcePdf = new PdfDocument(new PdfReader(file)))
//         {
//             merger.Merge(sourcePdf, 1, sourcePdf.GetNumberOfPages());
//         }
//     }
// }

// IronPDF (simple)
var merged = PdfDocument.Merge(pdfDocuments);
merged.SaveAs("merged.pdf");

// iText merger pattern (delete this)
// using (PdfDocument pdfDoc = new PdfDocument(writer))
// {
//     PdfMerger merger = new PdfMerger(pdfDoc);
//     foreach (string file in inputFiles)
//     {
//         using (PdfDocument sourcePdf = new PdfDocument(new PdfReader(file)))
//         {
//             merger.Merge(sourcePdf, 1, sourcePdf.GetNumberOfPages());
//         }
//     }
// }

// IronPDF (simple)
var merged = PdfDocument.Merge(pdfDocuments);
merged.SaveAs("merged.pdf");

' iText merger pattern (delete this)
' Using pdfDoc As New PdfDocument(writer)
'     Dim merger As New PdfMerger(pdfDoc)
'     For Each file As String In inputFiles
'         Using sourcePdf As New PdfDocument(New PdfReader(file))
'             merger.Merge(sourcePdf, 1, sourcePdf.GetNumberOfPages())
'         End Using
'     Next
' End Using

' IronPDF (simple)
Dim merged = PdfDocument.Merge(pdfDocuments)
merged.SaveAs("merged.pdf")

' iText merger pattern (delete this)
' Using pdfDoc As New PdfDocument(writer)
'     Dim merger As New PdfMerger(pdfDoc)
'     For Each file As String In inputFiles
'         Using sourcePdf As New PdfDocument(New PdfReader(file))
'             merger.Merge(sourcePdf, 1, sourcePdf.GetNumberOfPages())
'         End Using
'     Next
' End Using

' IronPDF (simple)
Dim merged = PdfDocument.Merge(pdfDocuments)
merged.SaveAs("merged.pdf")

Migration Checklist

Pre-Migration

Inventory all iText API calls in codebase
Identify programmatic PDF construction patterns (Paragraph, Table, Cell)
Document HtmlConverter usage (pdfHTML add-on)
Assess AGPL compliance risk
Obtain IronPDF license key

Code Migration

Remove iText NuGet packages: dotnet remove package itext (and the deprecated itext7 alias, plus itext.pdfhtml / iTextSharp if present)
Install IronPDF NuGet package: dotnet add package IronPdf
Update namespace imports (using iText.* → using IronPdf)
Replace PdfWriter/Document pattern with ChromePdfRenderer
Convert Paragraph/Table/Cell to HTML elements
Replace HtmlConverter.ConvertToPdf() with RenderHtmlAsPdf()
Update merge operations to PdfDocument.Merge()
Add license key initialization at startup

Testing

Test all PDF generation paths
Verify visual output matches expectations
Test with complex HTML/CSS content
Benchmark performance

Post-Migration

Remove iText license files and references
Update documentation
Cancel iText subscription (if applicable)
Archive legacy iText code

Please note: iText is a registered trademark of its respective owner. This site is not affiliated with, endorsed by, or sponsored by iText Group. All product names, logos, and brands are property of their respective owners. Comparisons are for informational purposes only and reflect publicly available information at the time of writing.

Curtis Chau

Chat with engineering team now

Technical Writer

Curtis Chau holds a Bachelor’s degree in Computer Science (Carleton University) and specializes in front-end development with expertise in Node.js, TypeScript, JavaScript, and React. Passionate about crafting intuitive and aesthetically pleasing user interfaces, Curtis enjoys working with modern frameworks and creating well-structured, visually appealing manuals.

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