A Comparison between IronPDF and PSPDFKit

2.1. IronPDF Features

3.1. PSPDFKit Features

5.1 Using the Visual Studio NuGet Package Manager

The Visual Studio software provides the NuGet Package Manager option to install the package directly to the solution. The below screenshot shows how to open the NuGet Package Manager.

Once the Package Manager GUI opens, search for the keyword "IronPDF" in the Browse section, as in the below screenshot:

We need to select the IronPDF option in the search results and install the package.

5.2 Using the Visual Studio Command-Line

• In the Visual Studio menu, Go to Tools > NuGet Package manager > Package manager console
• Enter the following line in the package manager console tab:

Install-Package IronPdf

The IronPDF package will now be installed in the current project.

5.3 Direct Download from the NuGet Gallery

The third way is to download the NuGet package directly from the IronPDF NuGet Gallery web page.

• Select the download package option from the menu on the right-hand side.
• Double-click the downloaded package; it will be installed automatically.
• Next, reload the solution and begin using it in the project.

5.4 Direct Download from IronPDF's Official Website

Visit the IronPDF Download Page to download the latest package directly from the website. After the download, follow the steps below to add the package to the project.

• Right-click the project from the solution window.
• Then, select "Add Reference" and browse the location of the downloaded reference.
• Next, click OK to add the reference.

6.1 Using the Visual Studio NuGet Package Manager

Developers can easily integrate PSPDFKit using the NuGet package manager. An example of how to do so is below.

After clicking on NuGet Package Manager in tools, a new window will appear with the search bar. Search for PSPDFKit. A list will appear.

In the above image, we can see the list of the related packages from the search. Next, select the desired PSPDFKit option and install the package.

6.2 Using the Visual Studio Command-Line

• In the Visual Studio menu, Go to Tools > NuGet Package manager > Package manager console

• Enter the following line in the package manager console tab:

Install-Package PSPDFKit.NET -Version 1.4.1

The package will now be installed in the current project.

6.3 Direct Download from the NuGet Gallery

The third way is to download the NuGet package directly from the PSPDFKit's NuGet Gallery page.

• Select the option to download the package from the right-hand menu.
• Double-click the downloaded package to start the installation process.
• Reload the solution and use it in your project.

6.4 Using the VSIX Extension

Instead of downloading the package locally using NuGet, you may use a configuration file to reference the package at a specific location. This is useful in cases in which you have machines that share resources on a network.

• Download the VSIX extension from the PSPDFKit download page and extract the zip.
• Then, create a nuget.config file in the same directory as your .NET Application.
• The file should contain this XML code.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <packageSources>
        <add key="PSPDFKitSource" value="path\to\directoryContainingNupkg" />
    </packageSources>
</configuration>

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <packageSources>
        <add key="PSPDFKitSource" value="path\to\directoryContainingNupkg" />
    </packageSources>
</configuration>

• Next, open Visual Studio and configure the following package under the reference tab.

7.1. Merging PDFs using IronPDF

IronPDF's IronPdf.PdfDocument.Merge class makes it easy to combine two or more PDF documents in C#.NET by using simple and easy-to-understand code.

using IronPdf;

// Example HTML content for PDF_A
var html_a = @"<p> [PDF_A] </p>
    <p> [PDF_A] 1st Page </p>
    <div style='page-break-after: always;'></div>
    <p> [PDF_A] 2nd Page</p>";

// Example HTML content for PDF_B
var html_b = @"<p> [PDF_B] </p>
    <p> [PDF_B] 1st Page </p>
    <div style='page-break-after: always;'></div>
    <p> [PDF_B] 2nd Page</p>";

// Initialize renderer
var Renderer = new IronPdf.ChromePdfRenderer();

// Render HTML to PDFs
using var pdfdoc_a = Renderer.RenderHtmlAsPdf(html_a);
using var pdfdoc_b = Renderer.RenderHtmlAsPdf(html_b);

// Merge PDFs
using var merged = IronPdf.PdfDocument.Merge(pdfdoc_a, pdfdoc_b);

// Save merged PDF to file
merged.SaveAs("Merged.pdf");

using IronPdf;

// Example HTML content for PDF_A
var html_a = @"<p> [PDF_A] </p>
    <p> [PDF_A] 1st Page </p>
    <div style='page-break-after: always;'></div>
    <p> [PDF_A] 2nd Page</p>";

// Example HTML content for PDF_B
var html_b = @"<p> [PDF_B] </p>
    <p> [PDF_B] 1st Page </p>
    <div style='page-break-after: always;'></div>
    <p> [PDF_B] 2nd Page</p>";

// Initialize renderer
var Renderer = new IronPdf.ChromePdfRenderer();

// Render HTML to PDFs
using var pdfdoc_a = Renderer.RenderHtmlAsPdf(html_a);
using var pdfdoc_b = Renderer.RenderHtmlAsPdf(html_b);

// Merge PDFs
using var merged = IronPdf.PdfDocument.Merge(pdfdoc_a, pdfdoc_b);

// Save merged PDF to file
merged.SaveAs("Merged.pdf");

7.2. Merging PDFs using PSPDFKit GMBH

The accompanying code demonstrates how to use the PSPDFKit Document Editor to merge two or more PDFs.

using PSPDFKit;
using PSPDFKit.Providers;

namespace PdfEditing
{
    public sealed class Program
    {
        public static void Main(string[] args)
        {
            var documentEditor = new DocumentEditor();
            // Import the first document to merge
            documentEditor.ImportDocument(0, DocumentEditor.IndexPosition.BeforeIndex, new FileDataProvider("Assets/dog.pdf"));
            // Import the second document to merge
            documentEditor.ImportDocument(0, DocumentEditor.IndexPosition.BeforeIndex, new FileDataProvider("Assets/cat.pdf"));

            // Save the merged document to a new file
            documentEditor.SaveDocument(new FileDataProvider("dogCatPair.pdf"));
        }
    }
}

using PSPDFKit;
using PSPDFKit.Providers;

namespace PdfEditing
{
    public sealed class Program
    {
        public static void Main(string[] args)
        {
            var documentEditor = new DocumentEditor();
            // Import the first document to merge
            documentEditor.ImportDocument(0, DocumentEditor.IndexPosition.BeforeIndex, new FileDataProvider("Assets/dog.pdf"));
            // Import the second document to merge
            documentEditor.ImportDocument(0, DocumentEditor.IndexPosition.BeforeIndex, new FileDataProvider("Assets/cat.pdf"));

            // Save the merged document to a new file
            documentEditor.SaveDocument(new FileDataProvider("dogCatPair.pdf"));
        }
    }
}

8.1. Annotations using IronPDF

PDF annotations allow you to add "sticky note" style comments to PDF documents. The IronPdf.PdfDocument.AddTextAnnotation method and PdfDocument.TextAnnotation class allow annotations to be added programmatically. Coloring, size, opacity, icons, and editing are among the advanced text annotation options provided.

// Install-Package IronPdf

using IronPdf;

var pdf = PdfDocument.FromFile("existing.pdf");
var annotation = new IronPdf.Annotations.TextAnnotation()
{
    Title = "This is the major title",
    Subject = "This is a subtitle",
    Contents = "This is the long 'sticky note' comment content...",
    Icon = IronPdf.Annotations.TextAnnotation.AnnotationIcon.Help,
    Opacity = 0.9,
    Printable = false,
    Hidden = false,
    OpenByDefault = true,
    ReadOnly = false,
    Rotateable = true
};

// Add annotation to a specific page at given coordinates
pdf.AddTextAnnotation(annotation, pageIndex: 1, xPosition: 150, yPosition: 250);

// Save the updated PDF
pdf.SaveAs("updated_existing.pdf");

// Install-Package IronPdf

using IronPdf;

var pdf = PdfDocument.FromFile("existing.pdf");
var annotation = new IronPdf.Annotations.TextAnnotation()
{
    Title = "This is the major title",
    Subject = "This is a subtitle",
    Contents = "This is the long 'sticky note' comment content...",
    Icon = IronPdf.Annotations.TextAnnotation.AnnotationIcon.Help,
    Opacity = 0.9,
    Printable = false,
    Hidden = false,
    OpenByDefault = true,
    ReadOnly = false,
    Rotateable = true
};

// Add annotation to a specific page at given coordinates
pdf.AddTextAnnotation(annotation, pageIndex: 1, xPosition: 150, yPosition: 250);

// Save the updated PDF
pdf.SaveAs("updated_existing.pdf");

8.2. Annotations using PSPDFKit

For describing PDF annotations, PSPDFKit for .NET provides a JSON-based API. This gives you a lot of freedom when it comes to dealing with annotations since you may have handmade annotations in your code or a JSON file that you import as needed.

using Newtonsoft.Json.Linq;
using PSPDFKit;
using PSPDFKit.Providers;

namespace Annotations
{
    public sealed class Program
    {
        public static void Main(string[] args)
        {
            var provider = new FileDataProvider("document.pdf");
            var document = new Document(provider);
            var annotationProvider = document.GetAnnotationProvider();

            // JSON structure for a text annotation
            var textAnJson = new JObject
            {
                { "text", "Hello from PSPDFKit" },
                { "bbox", new JArray(10, 10, 400, 400) },
                { "creatorName", "Will" },
                { "type", "pspdfkit/text" },
                { "updatedAt", "2021-01-01T00:00:00Z" },
                { "v", 1 }
            };

            // Add the annotation to the document
            annotationProvider.AddAnnotationJson(textAnJson);

            // Save the updated document
            document.Save(new DocumentSaveOptions());
        }
    }
}

using Newtonsoft.Json.Linq;
using PSPDFKit;
using PSPDFKit.Providers;

namespace Annotations
{
    public sealed class Program
    {
        public static void Main(string[] args)
        {
            var provider = new FileDataProvider("document.pdf");
            var document = new Document(provider);
            var annotationProvider = document.GetAnnotationProvider();

            // JSON structure for a text annotation
            var textAnJson = new JObject
            {
                { "text", "Hello from PSPDFKit" },
                { "bbox", new JArray(10, 10, 400, 400) },
                { "creatorName", "Will" },
                { "type", "pspdfkit/text" },
                { "updatedAt", "2021-01-01T00:00:00Z" },
                { "v", 1 }
            };

            // Add the annotation to the document
            annotationProvider.AddAnnotationJson(textAnJson);

            // Save the updated document
            document.Save(new DocumentSaveOptions());
        }
    }
}

IronPDF: Complete Bootstrap Framework Support

IronPDF's Chromium-based rendering engine provides full support for:

• Bootstrap 5: Complete flexbox layouts, CSS Grid, utility classes, and all components
• Bootstrap 4: Full card systems, navigation, flex utilities, responsive design
• Tailwind CSS: All utility classes render accurately
• Foundation: Complete grid system and component library
• Modern CSS3: Flexbox, CSS Grid, custom properties, animations

Real-world validation: IronPDF renders the Bootstrap homepage and all official examples with pixel-perfect accuracy.

PSPDFKit: No HTML-to-PDF Conversion

PSPDFKit focuses on PDF viewing, annotation, and manipulation rather than HTML-to-PDF conversion:

• No HTML rendering engine: PSPDFKit does not convert HTML to PDF
• Viewer-focused: Designed for PDF display and interaction, not generation
• External conversion required: HTML-to-PDF must be handled by separate tools
• JavaScript SDK: Client-side PDF viewer, not a server-side generation library

Development impact: Teams needing HTML-to-PDF conversion must integrate additional tools alongside PSPDFKit, increasing complexity and maintenance requirements.

For comprehensive Bootstrap framework guidance and modern CSS rendering capabilities, see the Bootstrap & Flexbox CSS Guide.