Message icon
Skip to footer content
  1. IronPDF
  2. IronPDF Blog
  3. Using IronPDF
  4. PDF Api .NET Core
USING IRONPDF

PDF API for .NET Core: The Complete Guide to Generating and Editing PDF Documents

Curtis Chau
Curtis Chau
Published:

PDF API for .NET Core: The Complete Guide to Generating and Editing PDF Documents: Image 1 - The Best PDF API for .NET Core: A Complete Guide

Tired of wrestling with clunky, feature-limited libraries just to generate a simple invoice or report in your .NET Core application? Working with PDFs should be straightforward, but often requires stitching together multiple tools to handle everything from basic creation to complex needs like needing to extract images or split PDFs, apply digital signatures, and create form fields.

Enter IronPDF. This isn't just another library; it's an enterprise-grade PDF API for .NET Core. IronPDF gives you the power to programmatically create, convert, and edit sophisticated PDF documents with minimal, readable code.

Start your free trial to explore the full capabilities of this feature-rich library.

What Makes the Right Tool for PDF Generation in .NET Core?

The right tool for generating PDF files combines cross-platform compatibility, a fluent API, and comprehensive document manipulation features. A robust PDF API should support .NET Framework and .NET Core equally while handling common requirements like HTML conversion, PDF forms, and server-side processing.

IronPDF stands out as a PDF library built specifically for .NET applications. It runs seamlessly on Windows, Linux, and macOS, making it ideal for web applications deployed across different server environments. The library supports ASP.NET Core projects out of the box, requiring only a simple NuGet packages installation to get started.

Key capabilities include generating PDFs from HTML, converting existing documents to PDF format, managing form fields, adding bookmarks and hyperlinks, and applying digital signatures, all through an intuitive API that keeps code clean and maintainable.

How Can Developers Handle Generating PDFs from HTML?

HTML to PDF conversion is a common requirement for generating dynamic content like invoices, reports, and certificates. IronPDF's ChromePdfRenderer handles this conversion while preserving CSS formatting, fonts, and images exactly as they appear in browsers.

using IronPdf;
// Create a new renderer instance
var renderer = new ChromePdfRenderer();
// Define HTML content with styling
var html = @"<html>
<head><style>body { font-family: Arial; font-size: 14px; }</style></head>
<body><h1>Sales Report</h1><p>Generated dynamically with full formatting support.</p></body>
</html>";
// Convert HTML string to PDF document
var document = renderer.RenderHtmlAsPdf(html);
// Save the PDF file
document.SaveAs("report.pdf");
using IronPdf;
// Create a new renderer instance
var renderer = new ChromePdfRenderer();
// Define HTML content with styling
var html = @"<html>
<head><style>body { font-family: Arial; font-size: 14px; }</style></head>
<body><h1>Sales Report</h1><p>Generated dynamically with full formatting support.</p></body>
</html>";
// Convert HTML string to PDF document
var document = renderer.RenderHtmlAsPdf(html);
// Save the PDF file
document.SaveAs("report.pdf");
IRON VB CONVERTER ERROR developers@ironsoftware.com
$vbLabelText   $csharpLabel

Output PDF Document

PDF API for .NET Core: The Complete Guide to Generating and Editing PDF Documents: Image 2 - Generated PDF file

The ChromePdfRenderer class converts HTML strings, files, or URLs into PDF documents. The example above demonstrates creating a simple PDF document from an HTML string. The renderer respects all CSS properties including font size, margins, and page layout, ensuring pixel-perfect output for professional documents.

For applications requiring PDF generation from live web pages, use RenderUrlAsPdf to capture any URL as a PDF file while executing JavaScript and loading external assets.

How Do You Convert Existing Documents to Other Formats?

Beyond HTML, IronPDF supports PDF conversion from multiple file formats including DOCX, images, and Markdown. This flexibility allows developers to build document processing pipelines that handle various input types.

using IronPdf;
// Convert a DOCX file to PDF format
var doc = new DocxToPdfRenderer().RenderDocxAsPdf("contract.docx");
doc.SaveAs("contract.pdf");
// Convert multiple images to a single PDF
var images = new[] { "page1.png", "page2.png", "page3.png" };
var pdfFromImages = new ImageToPdfConverter().ImageToPdf(images);
pdfFromImages.SaveAs("scanned-document.pdf");
using IronPdf;
// Convert a DOCX file to PDF format
var doc = new DocxToPdfRenderer().RenderDocxAsPdf("contract.docx");
doc.SaveAs("contract.pdf");
// Convert multiple images to a single PDF
var images = new[] { "page1.png", "page2.png", "page3.png" };
var pdfFromImages = new ImageToPdfConverter().ImageToPdf(images);
pdfFromImages.SaveAs("scanned-document.pdf");
IRON VB CONVERTER ERROR developers@ironsoftware.com
$vbLabelText   $csharpLabel

Example Input DOCX File vs. Output PDF File

PDF API for .NET Core: The Complete Guide to Generating and Editing PDF Documents: Image 3 - DOCX to PDF conversion output comparison

The DOCX to PDF conversion feature transforms Word documents while maintaining formatting integrity. This proves invaluable when you need to convert PDF files from existing documents created in Microsoft Word. The image conversion handles various formats and optimizes file size automatically.

What Advanced Features Support Enterprise-Grade Applications?

Enterprise applications demand features beyond basic PDF creation. IronPDF provides digital signatures, form field management, and document security to protect documents and ensure authenticity.

using IronPdf;
using IronPdf.Signing;
using System;
using System.IO;
// Load an existing PDF document
var pdf = PdfDocument.FromFile("agreement.pdf");
// Add a digital signature
var signature = new PdfSignature("certificate.pfx", "password");
pdf.Sign(signature);
// Create and fill PDF forms programmatically
pdf.Form.FindFormField("CustomerName").Value = "Acme Corporation";
pdf.Form.FindFormField("Date").Value = DateTime.Now.ToString("yyyy-MM-dd");
pdf.SaveAs("signed-agreement.pdf");
using IronPdf;
using IronPdf.Signing;
using System;
using System.IO;
// Load an existing PDF document
var pdf = PdfDocument.FromFile("agreement.pdf");
// Add a digital signature
var signature = new PdfSignature("certificate.pfx", "password");
pdf.Sign(signature);
// Create and fill PDF forms programmatically
pdf.Form.FindFormField("CustomerName").Value = "Acme Corporation";
pdf.Form.FindFormField("Date").Value = DateTime.Now.ToString("yyyy-MM-dd");
pdf.SaveAs("signed-agreement.pdf");
IRON VB CONVERTER ERROR developers@ironsoftware.com
$vbLabelText   $csharpLabel

Example Verified Signature on a PDF File

PDF API for .NET Core: The Complete Guide to Generating and Editing PDF Documents: Image 4 - Verified signature on a PDF

Digital signatures verify document authenticity using industry-standard certificates. The PDF forms functionality lets you create interactive form fields, populate them with data, and export form data for processing. You can also encrypt PDF files with passwords to control access and editing permissions.

Additional advanced features include the ability to split PDFs into separate files, merge multiple documents, add bookmarks for navigation, and extract images or text from existing PDF documents.

How Can Developers Edit and Manipulate PDF Documents?

Editing existing PDF documents is straightforward with IronPDF's manipulation API. Add headers, footers, watermarks, and page numbers to any PDF file programmatically.

using IronPdf;
using System.IO;
// Open an existing PDF document
var document = PdfDocument.FromFile("original.pdf");
// Add headers and footers
var renderer = new ChromePdfRenderer();
document.AddHtmlHeaders(new HtmlHeaderFooter()
{
    HtmlFragment = "<div style='text-align:center'>Confidential Document</div>"
});
// Save to byte array for streaming or storage
byte[] pdfBytes = document.BinaryData;
// Or save to a stream
var stream = new MemoryStream();
document.Stream.CopyTo(stream);
// Import pages from another PDF
var appendix = PdfDocument.FromFile("appendix.pdf");
document.AppendPdf(appendix);
document.SaveAs("final-document.pdf");
using IronPdf;
using System.IO;
// Open an existing PDF document
var document = PdfDocument.FromFile("original.pdf");
// Add headers and footers
var renderer = new ChromePdfRenderer();
document.AddHtmlHeaders(new HtmlHeaderFooter()
{
    HtmlFragment = "<div style='text-align:center'>Confidential Document</div>"
});
// Save to byte array for streaming or storage
byte[] pdfBytes = document.BinaryData;
// Or save to a stream
var stream = new MemoryStream();
document.Stream.CopyTo(stream);
// Import pages from another PDF
var appendix = PdfDocument.FromFile("appendix.pdf");
document.AppendPdf(appendix);
document.SaveAs("final-document.pdf");
IRON VB CONVERTER ERROR developers@ironsoftware.com
$vbLabelText   $csharpLabel

Example Output

PDF API for .NET Core: The Complete Guide to Generating and Editing PDF Documents: Image 5 - Example edited and appended PDF file

The editing capabilities extend to modifying page orientation, applying custom watermarks, adjusting fonts, and compressing output for reduced file size. These features make IronPDF suitable for document automation workflows in any .NET application running on your preferred system.

Why Choose This Library for Your Next .NET Application?

IronPDF combines professional version capabilities with straightforward licensing costs. Unlike open source alternatives that may lack enterprise support or comprehensive features, IronPDF offers a commercial license that includes dedicated engineering assistance and regular updates, supporting business growth through reliable tooling.

The library integrates with any ASP.NET Core, Blazor, or console application through standard NuGet packages. Whether building server-side report generators or client-facing web applications, the consistent API handles PDF generation, conversion, and manipulation across all .NET platforms.

Purchase a license to unlock the full potential of this feature-rich PDF API for commercial use in production environments.

Conclusion

Working with PDF documents in .NET Core doesn't have to be complicated. IronPDF’s intuitive and fluent API allows developers to quickly implement programmatic PDF generation, powerful HTML conversion, and sophisticated document editing, all with minimal code.

By supporting features like digital signing, form filling, and document merging, IronPDF ensures your application can handle every PDF challenge. Choose IronPDF to ensure a reliable, high-quality, and maintainable solution for all your document processing needs.

Curtis Chau
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.

...

Read More

Related Articles

30-day trial → Full product. No limits. No card. Start Free Trial