iTextSharp C# HTML to PDF Alternative for .NET Core

iText 7 is a powerful and flexible PDF library that provides extensive PDF manipulation capabilities, including document creation, encryption, and signing. However, its core library does not support HTML-to-PDF conversion natively.

Key Features

• Low-Level PDF Customization – Provides detailed control over PDF structure, metadata, and rendering.
• Accessibility & Compliance: Generates PDF/A, PDF/UA, and PDF/X for long-term archiving and accessibility compliance.
• HTML-to-PDF Conversion: The paid pdfHTML add-on enables conversion of HTML content into PDFs.
• Java & .NET Support: Primarily designed for Java, with C# support via iText 7 for .NET.
• PDF Form Management: Create and edit AcroForms and XFA Forms for interactive PDF forms.

Best for: Developers who need a highly customizable PDF solution and are willing to purchase additional add-ons for extended features.

IronPDF boasts a rich set of features for working with PDF documents. These range from PDF creation, to PDF manipulation and security. To get a clearer idea of the extensive range of features this library has to offer, we will be taking a look at a select few key features.

HTML to PDF Conversion

Convert HTML content into high-quality PDF documents with IronPDF’s powerful rendering engine. IronPDF’s renderer doesn’t simply convert HTML content either; with it, you will be able to maintain all original CSS styling and JavaScript interactivity.

using IronPdf;

public class Program
{
    static void Main(string[] args)
    {
        // Create a new ChromePdfRenderer instance for rendering HTML to PDF
        ChromePdfRenderer renderer = new ChromePdfRenderer();

        // Render the specified HTML file as a PDF document
        PdfDocument pdf = renderer.RenderHtmlFileAsPdf("example.html");

        // Save the rendered PDF to the specified file path
        pdf.SaveAs("HtmlToPdf.pdf");
    }
}

using IronPdf;

public class Program
{
    static void Main(string[] args)
    {
        // Create a new ChromePdfRenderer instance for rendering HTML to PDF
        ChromePdfRenderer renderer = new ChromePdfRenderer();

        // Render the specified HTML file as a PDF document
        PdfDocument pdf = renderer.RenderHtmlFileAsPdf("example.html");

        // Save the rendered PDF to the specified file path
        pdf.SaveAs("HtmlToPdf.pdf");
    }
}

Input HTML

Output PDF

In this code example, we have first created a new ChromePdfRenderer instance, which gives us access to the powerful rendering engine IronPDF uses to render HTML to PDF. Then, we pass an HTML file to the RenderHtmlFileAsPdf() method, which in turn renders the HTML into a PDF, stored in the PdfDocument object. Finally, we will save the PDF to the specified file location.

URL to PDF

For developers looking to convert URL content into PDFs, look no further than IronPDF. With this library, you will be able to create pixel-perfect PDF documents through the use of the ChromePdfRenderer rendering engine, which will maintain all original styling and layouts when it renders the URL to PDF. For this example, we will be using this URL to demonstrate how IronPDF can handle more complex CSS styling.

using IronPdf;

public class Program
{
    static void Main(string[] args)
    {
        // Create a new ChromePdfRenderer instance
        ChromePdfRenderer renderer = new ChromePdfRenderer();

        // Render the specified URL as a PDF document
        PdfDocument pdf = renderer.RenderUrlAsPdf("https://www.apple.com");

        // Save the rendered PDF to the specified file path
        pdf.SaveAs("UrlToPdf.pdf");
    }
}

using IronPdf;

public class Program
{
    static void Main(string[] args)
    {
        // Create a new ChromePdfRenderer instance
        ChromePdfRenderer renderer = new ChromePdfRenderer();

        // Render the specified URL as a PDF document
        PdfDocument pdf = renderer.RenderUrlAsPdf("https://www.apple.com");

        // Save the rendered PDF to the specified file path
        pdf.SaveAs("UrlToPdf.pdf");
    }
}

PDF Output:

Much like in our HTML to PDF example, the first step to converting any URL to PDF using IronPDF is to first create a new ChromePdfRenderer instance. Once the method has rendered the URL content into a PDF format, using RenderUrlAsPdf, it saves the resulting PDF to a new PdfDocument object, before we use the SaveAs method to save the PDF.

PDF Signatures

Ensure the authenticity of your PDF document by applying a digital signature to your PDF documents. There are different methods of which developers might consider applying digital signatures such as digitally signing the PDF with a secure certificate, adding an image of a handwritten signature to a PDF, or stamping an image of the certificate onto the PDF itself.

using IronPdf;
using IronPdf.Signing;
using System.Security.Cryptography.X509Certificates;
using IronSoftware.Drawing;

public class Program
{
    static void Main(string[] args)
    {
        // Load the certificate used for signing the PDF
        X509Certificate2 cert = new X509Certificate2("IronSoftware.pfx", "your-password", X509KeyStorageFlags.Exportable);

        // Create a PdfSignature instance and set the signature image
        var sig = new PdfSignature(cert);
        sig.SignatureImage = new PdfSignatureImage("IronPdf.png", 0, new Rectangle(150, 100, 350, 250));

        // Sign the existing PDF file and save the signed version
        sig.SignPdfFile("product_report.pdf");
    }
}

using IronPdf;
using IronPdf.Signing;
using System.Security.Cryptography.X509Certificates;
using IronSoftware.Drawing;

public class Program
{
    static void Main(string[] args)
    {
        // Load the certificate used for signing the PDF
        X509Certificate2 cert = new X509Certificate2("IronSoftware.pfx", "your-password", X509KeyStorageFlags.Exportable);

        // Create a PdfSignature instance and set the signature image
        var sig = new PdfSignature(cert);
        sig.SignatureImage = new PdfSignatureImage("IronPdf.png", 0, new Rectangle(150, 100, 350, 250));

        // Sign the existing PDF file and save the signed version
        sig.SignPdfFile("product_report.pdf");
    }
}

Output PDF

For this example, we have loaded in our certificate object, created a visual representation of the signature, or in our case the IronPDF image, and created a new PdfSignature object, which handles the signing of the PDF document itself. Finally, we used the SignPdfFile to sign and save our PDF document.

If you want to explore more of the features IronPDF has to offer, be sure to check out its informative features page, or the How-to Guides which contain in-depth code examples for each feature.

iText7 offers a wide range of features for customizing and enhancing your PDF documents. With extensive format support for various PDF standards and advanced PDF manipulation, there is a lot packed into this PDF library. However, as mentioned before, iText7 may require additional packages in order to carry out certain PDF-related tasks such as HTML to PDF.

HTML to PDF Conversion

Although iText7 by itself cannot handle HTML to PDF conversion, we can utilize the pdfHTML, a paid add-on found under iText7’s commercial licensing, to convert the HTML file we used in our IronPDF example into a PDF document.

using iText.Html2pdf;
using System.IO;

public class Program
{
    static void Main(string[] args)
    {
        // Open the HTML file stream
        using (FileStream htmlSource = File.Open("example.html", FileMode.Open))
        // Create the output PDF file stream
        using (FileStream pdf = File.Open("HtmlToPdfOutput.pdf", FileMode.Create))
        {
            // Initialize ConverterProperties for HTML to PDF conversion
            ConverterProperties converterProperties = new ConverterProperties();

            // Convert the HTML source to a PDF document
            HtmlConverter.ConvertToPdf(htmlSource, pdf, converterProperties);

            // Close the PDF file
            pdf.Close();
        }
    }
}

using iText.Html2pdf;
using System.IO;

public class Program
{
    static void Main(string[] args)
    {
        // Open the HTML file stream
        using (FileStream htmlSource = File.Open("example.html", FileMode.Open))
        // Create the output PDF file stream
        using (FileStream pdf = File.Open("HtmlToPdfOutput.pdf", FileMode.Create))
        {
            // Initialize ConverterProperties for HTML to PDF conversion
            ConverterProperties converterProperties = new ConverterProperties();

            // Convert the HTML source to a PDF document
            HtmlConverter.ConvertToPdf(htmlSource, pdf, converterProperties);

            // Close the PDF file
            pdf.Close();
        }
    }
}

Output PDF

For this example, we loaded in the HTML file and specified the file location to save the rendered PDF to. Then, using the ConvertToPdf method, we can easily convert the HTML file to a PDF document.

URL to PDF

Now, it's time to compare how iText7 measures up against IronPDF when it comes to converting URLs to PDF. For this, we will use the exact same URL as before to ensure a fair comparison.

using System;
using System.Net.Http;
using System.IO;
using iText.Html2pdf;

public class Program
{
    public static async System.Threading.Tasks.Task Main(string[] args)
    {
        string url = "https://www.apple.com";  // Replace with your target URL
        string outputPdfPath = "output.pdf";

        try
        {
            // Download HTML content from the URL
            using (HttpClient client = new HttpClient())
            {
                string htmlContent = await client.GetStringAsync(url);

                // Convert HTML to PDF
                using (FileStream pdfStream = new FileStream(outputPdfPath, FileMode.Create))
                {
                    ConverterProperties properties = new ConverterProperties();
                    HtmlConverter.ConvertToPdf(htmlContent, pdfStream, properties);
                }
            }

            Console.WriteLine("PDF created successfully: " + outputPdfPath);
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error: " + ex.Message);
        }
    }
}

using System;
using System.Net.Http;
using System.IO;
using iText.Html2pdf;

public class Program
{
    public static async System.Threading.Tasks.Task Main(string[] args)
    {
        string url = "https://www.apple.com";  // Replace with your target URL
        string outputPdfPath = "output.pdf";

        try
        {
            // Download HTML content from the URL
            using (HttpClient client = new HttpClient())
            {
                string htmlContent = await client.GetStringAsync(url);

                // Convert HTML to PDF
                using (FileStream pdfStream = new FileStream(outputPdfPath, FileMode.Create))
                {
                    ConverterProperties properties = new ConverterProperties();
                    HtmlConverter.ConvertToPdf(htmlContent, pdfStream, properties);
                }
            }

            Console.WriteLine("PDF created successfully: " + outputPdfPath);
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error: " + ex.Message);
        }
    }
}

Output PDF

As seen here, iText7’s approach to URL to PDF conversion is more manual and complex. First, we need to download the HTML content from the URL, before following similar steps as seen in the HTML to PDF example to render our URL content into a PDF document and save it. As you can see in the output image, iText7 wasn’t able to maintain much of the original styling and layout, unlike IronPDF.

PDF Signatures

using System.Security.Cryptography.X509Certificates;
using iText.Kernel.Pdf;
using iText.Signatures;
using iText.Bouncycastle.Crypto;
using iText.Commons.Bouncycastle.Cert;
using iText.Commons.Bouncycastle.Crypto;
using Org.BouncyCastle.Pkcs;
using Org.BouncyCastle.Crypto;
using iText.Bouncycastle.X509;
using iText.Kernel.Crypto;
using System.IO;

public class Program
{
    static void Main(string[] args)
    {
        string inputPdf = "input.pdf";       // PDF to be signed
        string outputPdf = "signed_output.pdf";  // Signed PDF output
        string pfxFile = "IronSoftware.pfx";  // Path to your PFX certificate
        string password = "Passw0rd";   // Password for PFX file

        try
        {
            // Load your certificate
            Pkcs12Store ks = new Pkcs12StoreBuilder().Build();
            using (FileStream fs = new FileStream(pfxFile, FileMode.Open, FileAccess.Read))
            {
                ks.Load(fs, password.ToCharArray());
            }

            string alias = null;
            foreach (string al in ks.Aliases)
            {
                if (ks.IsKeyEntry(al))
                {
                    alias = al;
                    break;
                }
            }

            if (alias == null)
            {
                throw new Exception("Alias not found in the PFX file.");
            }

            ICipherParameters pk = ks.GetKey(alias).Key;
            X509CertificateEntry[] chain = ks.GetCertificateChain(alias);

            // Convert BouncyCastle certificates to iText certificates
            var itextCertChain = new IX509Certificate[chain.Length];
            for (int i = 0; i < chain.Length; i++)
            {
                itextCertChain[i] = new X509CertificateBC(chain[i].Certificate);
            }

            // Create output PDF with signed content
            using (PdfReader reader = new PdfReader(inputPdf))
            using (FileStream os = new FileStream(outputPdf, FileMode.Create, FileAccess.Write))
            {
                PdfSigner signer = new PdfSigner(reader, os, new StampingProperties().UseAppendMode());

                // Set up the external signature (private key + digest algorithm)
                IPrivateKey iTextPrivateKey = new PrivateKeyBC(pk);
                IExternalSignature pks = new PrivateKeySignature(iTextPrivateKey, DigestAlgorithms.SHA256);
                IExternalDigest digest = new BouncyCastleDigest();

                // Perform the signing (detached signature)
                signer.SignDetached(digest, pks, itextCertChain, null, null, null, 0, PdfSigner.CryptoStandard.CMS);
            }

            Console.WriteLine($"PDF digitally signed successfully: {outputPdf}");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error signing PDF: {ex.Message}");
        }
    }
}

using System.Security.Cryptography.X509Certificates;
using iText.Kernel.Pdf;
using iText.Signatures;
using iText.Bouncycastle.Crypto;
using iText.Commons.Bouncycastle.Cert;
using iText.Commons.Bouncycastle.Crypto;
using Org.BouncyCastle.Pkcs;
using Org.BouncyCastle.Crypto;
using iText.Bouncycastle.X509;
using iText.Kernel.Crypto;
using System.IO;

public class Program
{
    static void Main(string[] args)
    {
        string inputPdf = "input.pdf";       // PDF to be signed
        string outputPdf = "signed_output.pdf";  // Signed PDF output
        string pfxFile = "IronSoftware.pfx";  // Path to your PFX certificate
        string password = "Passw0rd";   // Password for PFX file

        try
        {
            // Load your certificate
            Pkcs12Store ks = new Pkcs12StoreBuilder().Build();
            using (FileStream fs = new FileStream(pfxFile, FileMode.Open, FileAccess.Read))
            {
                ks.Load(fs, password.ToCharArray());
            }

            string alias = null;
            foreach (string al in ks.Aliases)
            {
                if (ks.IsKeyEntry(al))
                {
                    alias = al;
                    break;
                }
            }

            if (alias == null)
            {
                throw new Exception("Alias not found in the PFX file.");
            }

            ICipherParameters pk = ks.GetKey(alias).Key;
            X509CertificateEntry[] chain = ks.GetCertificateChain(alias);

            // Convert BouncyCastle certificates to iText certificates
            var itextCertChain = new IX509Certificate[chain.Length];
            for (int i = 0; i < chain.Length; i++)
            {
                itextCertChain[i] = new X509CertificateBC(chain[i].Certificate);
            }

            // Create output PDF with signed content
            using (PdfReader reader = new PdfReader(inputPdf))
            using (FileStream os = new FileStream(outputPdf, FileMode.Create, FileAccess.Write))
            {
                PdfSigner signer = new PdfSigner(reader, os, new StampingProperties().UseAppendMode());

                // Set up the external signature (private key + digest algorithm)
                IPrivateKey iTextPrivateKey = new PrivateKeyBC(pk);
                IExternalSignature pks = new PrivateKeySignature(iTextPrivateKey, DigestAlgorithms.SHA256);
                IExternalDigest digest = new BouncyCastleDigest();

                // Perform the signing (detached signature)
                signer.SignDetached(digest, pks, itextCertChain, null, null, null, 0, PdfSigner.CryptoStandard.CMS);
            }

            Console.WriteLine($"PDF digitally signed successfully: {outputPdf}");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error signing PDF: {ex.Message}");
        }
    }
}

Output PDF

As you can see, while iText7 is capable of digitally signing PDF documents, the process tends to be a lot more complex than with IronPDF. This code loads a PFX certificate and uses it to digitally sign a PDF. It extracts the private key and certificate, sets up the signer, and adds a detached signature to the PDF, then saves the signed document.

Key Advantages of IronPDF

IronPDF is renowned for its ease of use and optimization for high performance, offering a more straightforward API that simplifies common tasks such as HTML to PDF conversion. It provides high-level methods that abstract complex PDF processing tasks, allowing developers to generate, edit, and manipulate PDFs with minimal code. For multi-threaded or large-scale document processing, IronPDF supports parallel execution.

• Easy-to-use API – High-level methods simplify common tasks like HTML-to-PDF conversion.
• Minimal setup required – Integrates easily into .NET projects.
• Built-in parallel execution – Optimized for handling bulk PDF generation and conversion.
• Simplified API – Requires fewer lines of code to achieve results.

iText 7 - Powerful but Complex

iText 7, on the other hand, offers a more detailed and granular level of control, which can be advantageous for developers who require extensive customization. It provides a robust API for working with low-level PDF operations. However, due to its complexity, iText 7 often requires more code to achieve similar results compared to IronPDF.

• Granular PDF control – Ideal for enterprise applications requiring strict compliance (e.g., PDF/A, PDF/UA, digital signatures).
• Highly customizable – Offers low-level PDF manipulation for advanced use cases.
• Steeper learning curve – Requires more setup and configuration compared to IronPDF.
• More code-intensive – Common tasks often require longer implementations.

When selecting a PDF library for a .NET project, licensing and cost considerations are critical. Both IronPDF and iText 7 follow different licensing models, and choosing the right one depends on your project's requirements, budget, and compliance needs.

IronPDF Licensing and Cost

IronPDF follows a commercial licensing model, meaning that while it offers a free trial for commercial licensing, and is free for development and evaluation, a paid license is required for full production use. The pricing is transparent and depends on factors such as usage scale, number of developers, and project type.

IronPDF Licensing:

• Commercial licensing model (No open-source restrictions).
• Straightforward pricing based on developer or team licenses.
• No extra cost for HTML-to-PDF, PDF security, or other core features.
• Best for businesses that need a simple, cost-effective PDF solution.

Bottom Line: IronPDF includes all major features in a single license, making it a cost-effective choice for teams and businesses.

iText7 Licensing and Cost

iText7 operates under a dual licensing model, which includes:

1. AGPL (GNU Affero General Public License) – Free for open-source projects, but requires that the entire project using iText7 be open-source and AGPL-compliant. This means that any modifications or additions made to the project must also be shared publicly.
2. Commercial License – Required for any proprietary software or commercial applications that do not want to disclose their source code. The pricing structure varies based on usage, support level, and deployment scale.

For companies looking to integrate iText 7 into proprietary software, a commercial license is mandatory. The cost can be significant, especially for enterprise-level solutions, as it is priced on a per-developer scale, but it provides access to professional support and ensures legal compliance.

Why iText 7 Can Be More Expensive:

• Per-developer pricing – Each developer needs a separate license, increasing total costs for teams.
• Essential features require expensive add-ons:
  • pdfHTML (Paid) – Required for HTML-to-PDF conversion.
  • pdfOCR (Paid) – Needed for text recognition from images.
  • pdfCalligraph (Paid) – Improves text rendering and font support.
  • pdfRender (Paid) – Adds PDF-to-image conversion.
  • pdf2Data (Paid) – Extracts structured data from PDFs.
• Enterprise costs can quickly add up when multiple features and developers are needed.

Bottom Line: If your team requires multiple developers and key features like HTML-to-PDF and OCR, iText 7 can be significantly more expensive than IronPDF, which provides these features without extra costs.

Small vs. Enterprise Projects

For small to medium-sized projects that require quick implementation of PDF functionalities with minimal configuration, IronPDF is a compelling choice due to its user-friendly API and comprehensive feature set. Enterprise-level projects that demand extensive customization and adherence to specific PDF standards may benefit from the advanced capabilities of iText7, however, IronPDF also proves a strong candidate for this level of work due to its high performance, licensing options, and usability.

Academic and Commercial Use

In academic settings or open-source projects, iText 7's AGPL license allows for free usage, provided the project's license is compatible. For commercial applications, both IronPDF and iText 7 require the purchase of a commercial license. It's advisable to review the licensing terms of each library to ensure compliance with your project's objectives.