MIGRATION GUIDES

How to Migrate from Api2pdf to IronPDF in C#

Published:January 11, 2026

Api2pdf offers a cloud-based service for generating PDFs, but sending sensitive documents to external servers can lead to security risks, compliance issues, and ongoing costs that can add up over time. This guide provides a detailed migration path from Api2pdf to IronPDF—a native .NET PDF library that processes documents entirely on your own infrastructure, removing data transmission concerns and converting per-conversion costs into a one-time investment.

Why Consider Moving from Api2pdf?

While Api2pdf provides convenient cloud-based PDF generation, several factors lead development teams to look for on-premises alternatives for their PDF generation needs.

Security and Compliance Concerns

Api2pdf operates as a cloud-based service where your sensitive HTML and documents are sent to third-party servers for processing. This creates significant concerns for organizations handling regulated data.

Risk	Api2pdf	IronPDF
Data Transmission	All content sent to external servers	Processes locally on your infrastructure
GDPR Compliance	Data crosses jurisdictions	Data never leaves your environment
HIPAA Compliance	PHI transmitted externally	PHI stays within your systems
SOC 2	Third-party dependency	Full control over data handling
PCI DSS	Card data potentially exposed	No external transmission

Cost Accumulation Over Time

Api2pdf charges approximately $0.005 per conversion indefinitely, while IronPDF offers a one-time perpetual license. For applications generating significant PDF volumes, the cost difference becomes substantial:

Volume	Api2pdf (Annual)	IronPDF (One-Time)
10,000 PDFs/month	~$600/year	$749 (Lite)
50,000 PDFs/month	~$3,000/year	$749 (Lite)
100,000 PDFs/month	~$6,000/year	$1,499 (Plus)

IronPDF pays for itself within months for most production applications.

Performance and Availability

Api2pdf requires network round-trips that add 2-5 seconds of latency to every PDF generation request. IronPDF processes locally in 100-500 milliseconds. Additionally, IronPDF works fully offline and in air-gapped environments—critical for applications that can't depend on external service availability.

Api2pdf vs. IronPDF: Key Differences

Aspect	Api2pdf	IronPDF
Data Handling	Sent to third-party cloud servers	Processed locally on your infrastructure
Pricing	Pay-per-conversion (~$0.005/PDF)	One-time perpetual license
Latency	2-5 seconds (network round-trip)	100-500ms (local processing)
Offline	Not available	Works fully offline
Installation	API key + HTTP client	Simple NuGet package
Compliance	GDPR/HIPAA concerns (data leaves network)	Full compliance control

Step-by-Step Migration Process

Step 1: Update NuGet Packages

Remove the Api2pdf package and install IronPDF:

# Remove Api2pdf
dotnet remove package Api2Pdf

# Install IronPDF
dotnet add package IronPdf

# Remove Api2pdf
dotnet remove package Api2Pdf

# Install IronPDF
dotnet add package IronPdf

SHELL

Or via Package Manager Console:

Uninstall-Package Api2Pdf
Install-Package IronPdf

Step 2: Update Namespace References

Replace Api2pdf namespaces with IronPDF:

// Remove these
using Api2Pdf;
using Api2Pdf.DotNet;

// Add these
using IronPdf;
using IronPdf.Rendering;

// Remove these
using Api2Pdf;
using Api2Pdf.DotNet;

// Add these
using IronPdf;
using IronPdf.Rendering;

Imports IronPdf
Imports IronPdf.Rendering

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Step 3: Configure the License Key

Set the IronPDF license key at application startup:

// Set once at application startup
IronPdf.License.LicenseKey = "YOUR-IRONPDF-LICENSE-KEY";

// Or configure via appsettings.json:
// { "IronPdf.LicenseKey": "YOUR-IRONPDF-LICENSE-KEY" }

// Set once at application startup
IronPdf.License.LicenseKey = "YOUR-IRONPDF-LICENSE-KEY";

// Or configure via appsettings.json:
// { "IronPdf.LicenseKey": "YOUR-IRONPDF-LICENSE-KEY" }

' Set once at application startup
IronPdf.License.LicenseKey = "YOUR-IRONPDF-LICENSE-KEY"

' Or configure via appsettings.json:
' { "IronPdf.LicenseKey": "YOUR-IRONPDF-LICENSE-KEY" }

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Step 4: Remove API Key Configuration

IronPDF runs locally and doesn't require API keys:

// Remove this Api2pdf pattern
var client = new Api2PdfClient("API_KEY");

// Just create the renderer directly
var renderer = new ChromePdfRenderer();

// Remove this Api2pdf pattern
var client = new Api2PdfClient("API_KEY");

// Just create the renderer directly
var renderer = new ChromePdfRenderer();

' Remove this Api2pdf pattern
Dim client = New Api2PdfClient("API_KEY")

' Just create the renderer directly
Dim renderer = New ChromePdfRenderer()

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Complete API Migration Reference

Core Class Mapping

Api2pdf Class	IronPDF Equivalent
`Api2PdfClient`	`ChromePdfRenderer`
`Api2PdfResult`	`PdfDocument`
`HeadlessChromeOptions`	`ChromePdfRenderOptions`

Method Mapping

Api2pdf Method	IronPDF Method
`client.HeadlessChrome.FromHtmlAsync(html)`	`renderer.RenderHtmlAsPdf(html)`
`client.HeadlessChrome.FromUrlAsync(url)`	`renderer.RenderUrlAsPdf(url)`
`response.Pdf` (URL)	`pdf.SaveAs(path)`
`response.Pdf` (download)	`pdf.BinaryData`
`client.PdfSharp.MergePdfsAsync(urls)`	`PdfDocument.Merge(pdfs)`
`client.PdfSharp.SetPasswordAsync(url, pwd)`	`pdf.SecuritySettings.OwnerPassword`

Rendering Options Mapping

Api2pdf Option	IronPDF Option
`Landscape = true`	`RenderingOptions.PaperOrientation = Landscape`
`PageSize = "A4"`	`RenderingOptions.PaperSize = PdfPaperSize.A4`
`PrintBackground = true`	`RenderingOptions.PrintHtmlBackgrounds = true`
`MarginTop`, etc.	`RenderingOptions.MarginTop`, etc.
`Delay = 5000`	`RenderingOptions.WaitFor.RenderDelay(5000)`

Code Migration Examples

HTML to PDF Conversion

The most common Api2pdf operation demonstrates the fundamental shift—from cloud API calls to local processing.

Api2pdf Implementation:

// NuGet: Install-Package Api2Pdf.DotNet
using System;
using System.Threading.Tasks;
using Api2Pdf.DotNet;

class Program
{
    static async Task Main(string[] args)
    {
        var a2pClient = new Api2PdfClient("your-api-key");
        var apiResponse = await a2pClient.HeadlessChrome.FromHtmlAsync("<h1>Hello World</h1>");
        Console.WriteLine(apiResponse.Pdf);
    }
}

// NuGet: Install-Package Api2Pdf.DotNet
using System;
using System.Threading.Tasks;
using Api2Pdf.DotNet;

class Program
{
    static async Task Main(string[] args)
    {
        var a2pClient = new Api2PdfClient("your-api-key");
        var apiResponse = await a2pClient.HeadlessChrome.FromHtmlAsync("<h1>Hello World</h1>");
        Console.WriteLine(apiResponse.Pdf);
    }
}

Imports System
Imports System.Threading.Tasks
Imports Api2Pdf.DotNet

Module Program
    Async Function Main(args As String()) As Task
        Dim a2pClient = New Api2PdfClient("your-api-key")
        Dim apiResponse = Await a2pClient.HeadlessChrome.FromHtmlAsync("<h1>Hello World</h1>")
        Console.WriteLine(apiResponse.Pdf)
    End Function
End Module

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IronPDF Implementation:

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

class Program
{
    static void Main(string[] args)
    {
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");
        pdf.SaveAs("output.pdf");
        Console.WriteLine("PDF created successfully");
    }
}

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

class Program
{
    static void Main(string[] args)
    {
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>");
        pdf.SaveAs("output.pdf");
        Console.WriteLine("PDF created successfully");
    }
}

Imports System
Imports IronPdf

Class Program
    Shared Sub Main(ByVal args As String())
        Dim renderer = New ChromePdfRenderer()
        Dim pdf = renderer.RenderHtmlAsPdf("<h1>Hello World</h1>")
        pdf.SaveAs("output.pdf")
        Console.WriteLine("PDF created successfully")
    End Sub
End Class

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IronPDF eliminates the network round-trip, API key management, and the separate download step required by Api2pdf's URL-based response pattern.

URL to PDF Conversion

Api2pdf Implementation:

// NuGet: Install-Package Api2Pdf.DotNet
using System;
using System.Threading.Tasks;
using Api2Pdf.DotNet;

class Program
{
    static async Task Main(string[] args)
    {
        var a2pClient = new Api2PdfClient("your-api-key");
        var apiResponse = await a2pClient.HeadlessChrome.FromUrlAsync("https://www.example.com");
        Console.WriteLine(apiResponse.Pdf);
    }
}

// NuGet: Install-Package Api2Pdf.DotNet
using System;
using System.Threading.Tasks;
using Api2Pdf.DotNet;

class Program
{
    static async Task Main(string[] args)
    {
        var a2pClient = new Api2PdfClient("your-api-key");
        var apiResponse = await a2pClient.HeadlessChrome.FromUrlAsync("https://www.example.com");
        Console.WriteLine(apiResponse.Pdf);
    }
}

Imports System
Imports System.Threading.Tasks
Imports Api2Pdf.DotNet

Module Program
    Async Function Main(args As String()) As Task
        Dim a2pClient = New Api2PdfClient("your-api-key")
        Dim apiResponse = Await a2pClient.HeadlessChrome.FromUrlAsync("https://www.example.com")
        Console.WriteLine(apiResponse.Pdf)
    End Function
End Module

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IronPDF Implementation:

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

class Program
{
    static void Main(string[] args)
    {
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderUrlAsPdf("https://www.example.com");
        pdf.SaveAs("webpage.pdf");
        Console.WriteLine("PDF created from URL successfully");
    }
}

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

class Program
{
    static void Main(string[] args)
    {
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderUrlAsPdf("https://www.example.com");
        pdf.SaveAs("webpage.pdf");
        Console.WriteLine("PDF created from URL successfully");
    }
}

Imports System
Imports IronPdf

Module Program
    Sub Main(args As String())
        Dim renderer = New ChromePdfRenderer()
        Dim pdf = renderer.RenderUrlAsPdf("https://www.example.com")
        pdf.SaveAs("webpage.pdf")
        Console.WriteLine("PDF created from URL successfully")
    End Sub
End Module

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HTML File to PDF with Options

Api2pdf Implementation:

// NuGet: Install-Package Api2Pdf.DotNet
using System;
using System.IO;
using System.Threading.Tasks;
using Api2Pdf.DotNet;

class Program
{
    static async Task Main(string[] args)
    {
        var a2pClient = new Api2PdfClient("your-api-key");
        string html = File.ReadAllText("input.html");
        var options = new HeadlessChromeOptions
        {
            Landscape = true,
            PrintBackground = true
        };
        var apiResponse = await a2pClient.HeadlessChrome.FromHtmlAsync(html, options);
        Console.WriteLine(apiResponse.Pdf);
    }
}

// NuGet: Install-Package Api2Pdf.DotNet
using System;
using System.IO;
using System.Threading.Tasks;
using Api2Pdf.DotNet;

class Program
{
    static async Task Main(string[] args)
    {
        var a2pClient = new Api2PdfClient("your-api-key");
        string html = File.ReadAllText("input.html");
        var options = new HeadlessChromeOptions
        {
            Landscape = true,
            PrintBackground = true
        };
        var apiResponse = await a2pClient.HeadlessChrome.FromHtmlAsync(html, options);
        Console.WriteLine(apiResponse.Pdf);
    }
}

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IronPDF Implementation:

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

class Program
{
    static void Main(string[] args)
    {
        var renderer = new ChromePdfRenderer();
        renderer.RenderingOptions.PaperOrientation = IronPdf.Rendering.PdfPaperOrientation.Landscape;
        renderer.RenderingOptions.CssMediaType = IronPdf.Rendering.PdfCssMediaType.Print;
        string html = File.ReadAllText("input.html");
        var pdf = renderer.RenderHtmlAsPdf(html);
        pdf.SaveAs("output.pdf");
        Console.WriteLine("PDF created with options successfully");
    }
}

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

class Program
{
    static void Main(string[] args)
    {
        var renderer = new ChromePdfRenderer();
        renderer.RenderingOptions.PaperOrientation = IronPdf.Rendering.PdfPaperOrientation.Landscape;
        renderer.RenderingOptions.CssMediaType = IronPdf.Rendering.PdfCssMediaType.Print;
        string html = File.ReadAllText("input.html");
        var pdf = renderer.RenderHtmlAsPdf(html);
        pdf.SaveAs("output.pdf");
        Console.WriteLine("PDF created with options successfully");
    }
}

Imports System
Imports System.IO
Imports IronPdf

Module Program
    Sub Main(args As String())
        Dim renderer As New ChromePdfRenderer()
        renderer.RenderingOptions.PaperOrientation = IronPdf.Rendering.PdfPaperOrientation.Landscape
        renderer.RenderingOptions.CssMediaType = IronPdf.Rendering.PdfCssMediaType.Print
        Dim html As String = File.ReadAllText("input.html")
        Dim pdf = renderer.RenderHtmlAsPdf(html)
        pdf.SaveAs("output.pdf")
        Console.WriteLine("PDF created with options successfully")
    End Sub
End Module

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IronPDF configures rendering options directly on the renderer object rather than passing them as a separate options parameter to each API call.

Merging Multiple PDFs

Api2pdf Implementation:

using Api2Pdf.DotNet;

var a2pClient = new Api2PdfClient("YOUR_API_KEY");

var pdfUrls = new List<string>
{
    "https://example.com/pdf1.pdf",
    "https://example.com/pdf2.pdf",
    "https://example.com/pdf3.pdf"
};

var request = new PdfMergeRequest { Urls = pdfUrls };
var response = await a2pClient.PdfSharp.MergePdfsAsync(request);

if (response.Success)
{
    // Download merged PDF from response.Pdf URL
}

using Api2Pdf.DotNet;

var a2pClient = new Api2PdfClient("YOUR_API_KEY");

var pdfUrls = new List<string>
{
    "https://example.com/pdf1.pdf",
    "https://example.com/pdf2.pdf",
    "https://example.com/pdf3.pdf"
};

var request = new PdfMergeRequest { Urls = pdfUrls };
var response = await a2pClient.PdfSharp.MergePdfsAsync(request);

if (response.Success)
{
    // Download merged PDF from response.Pdf URL
}

Imports Api2Pdf.DotNet

Dim a2pClient = New Api2PdfClient("YOUR_API_KEY")

Dim pdfUrls = New List(Of String) From {
    "https://example.com/pdf1.pdf",
    "https://example.com/pdf2.pdf",
    "https://example.com/pdf3.pdf"
}

Dim request = New PdfMergeRequest With {.Urls = pdfUrls}
Dim response = Await a2pClient.PdfSharp.MergePdfsAsync(request)

If response.Success Then
    ' Download merged PDF from response.Pdf URL
End If

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IronPDF Implementation:

using IronPdf;

// Load PDFs from files
var pdf1 = PdfDocument.FromFile("document1.pdf");
var pdf2 = PdfDocument.FromFile("document2.pdf");
var pdf3 = PdfDocument.FromFile("document3.pdf");

// Merge all PDFs
var merged = PdfDocument.Merge(pdf1, pdf2, pdf3);
merged.SaveAs("merged.pdf");

using IronPdf;

// Load PDFs from files
var pdf1 = PdfDocument.FromFile("document1.pdf");
var pdf2 = PdfDocument.FromFile("document2.pdf");
var pdf3 = PdfDocument.FromFile("document3.pdf");

// Merge all PDFs
var merged = PdfDocument.Merge(pdf1, pdf2, pdf3);
merged.SaveAs("merged.pdf");

Imports IronPdf

' Load PDFs from files
Dim pdf1 = PdfDocument.FromFile("document1.pdf")
Dim pdf2 = PdfDocument.FromFile("document2.pdf")
Dim pdf3 = PdfDocument.FromFile("document3.pdf")

' Merge all PDFs
Dim merged = PdfDocument.Merge(pdf1, pdf2, pdf3)
merged.SaveAs("merged.pdf")

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IronPDF's static Merge method accepts multiple documents directly, eliminating the URL-based workflow.

Password-Protected PDFs

Api2pdf Implementation:

using Api2Pdf.DotNet;

var a2pClient = new Api2PdfClient("YOUR_API_KEY");

// Generate PDF first
var pdfResponse = await a2pClient.HeadlessChrome.FromHtmlAsync("<h1>Confidential</h1>");

// Then add password protection in separate call
var protectedResponse = await a2pClient.PdfSharp.SetPasswordAsync(
    pdfResponse.Pdf,
    "secretpassword"
);

using Api2Pdf.DotNet;

var a2pClient = new Api2PdfClient("YOUR_API_KEY");

// Generate PDF first
var pdfResponse = await a2pClient.HeadlessChrome.FromHtmlAsync("<h1>Confidential</h1>");

// Then add password protection in separate call
var protectedResponse = await a2pClient.PdfSharp.SetPasswordAsync(
    pdfResponse.Pdf,
    "secretpassword"
);

Imports Api2Pdf.DotNet

Dim a2pClient = New Api2PdfClient("YOUR_API_KEY")

' Generate PDF first
Dim pdfResponse = Await a2pClient.HeadlessChrome.FromHtmlAsync("<h1>Confidential</h1>")

' Then add password protection in separate call
Dim protectedResponse = Await a2pClient.PdfSharp.SetPasswordAsync(pdfResponse.Pdf, "secretpassword")

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IronPDF Implementation:

using IronPdf;

var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Confidential</h1>");

// Set security in one step
pdf.SecuritySettings.OwnerPassword = "owner123";
pdf.SecuritySettings.UserPassword = "user123";
pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.NoPrint;
pdf.SecuritySettings.AllowUserCopyPasteContent = false;
pdf.SecuritySettings.AllowUserEdits = PdfEditSecurity.NoEdit;

pdf.SaveAs("protected.pdf");

using IronPdf;

var renderer = new ChromePdfRenderer();
var pdf = renderer.RenderHtmlAsPdf("<h1>Confidential</h1>");

// Set security in one step
pdf.SecuritySettings.OwnerPassword = "owner123";
pdf.SecuritySettings.UserPassword = "user123";
pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.NoPrint;
pdf.SecuritySettings.AllowUserCopyPasteContent = false;
pdf.SecuritySettings.AllowUserEdits = PdfEditSecurity.NoEdit;

pdf.SaveAs("protected.pdf");

Imports IronPdf

Dim renderer As New ChromePdfRenderer()
Dim pdf = renderer.RenderHtmlAsPdf("<h1>Confidential</h1>")

' Set security in one step
pdf.SecuritySettings.OwnerPassword = "owner123"
pdf.SecuritySettings.UserPassword = "user123"
pdf.SecuritySettings.AllowUserPrinting = PdfPrintSecurity.NoPrint
pdf.SecuritySettings.AllowUserCopyPasteContent = False
pdf.SecuritySettings.AllowUserEdits = PdfEditSecurity.NoEdit

pdf.SaveAs("protected.pdf")

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IronPDF provides granular control over PDF permissions through the SecuritySettings property.

Headers and Footers

Api2pdf Implementation:

using Api2Pdf.DotNet;

var a2pClient = new Api2PdfClient("YOUR_API_KEY");

var options = new HeadlessChromeOptions
{
    HeaderHtml = "<div style='font-size:10px'>Company Header</div>",
    FooterHtml = "<div style='font-size:10px'>Page <span class='pageNumber'></span></div>"
};

var response = await a2pClient.HeadlessChrome.FromHtmlAsync(html, options);

using Api2Pdf.DotNet;

var a2pClient = new Api2PdfClient("YOUR_API_KEY");

var options = new HeadlessChromeOptions
{
    HeaderHtml = "<div style='font-size:10px'>Company Header</div>",
    FooterHtml = "<div style='font-size:10px'>Page <span class='pageNumber'></span></div>"
};

var response = await a2pClient.HeadlessChrome.FromHtmlAsync(html, options);

Imports Api2Pdf.DotNet

Dim a2pClient = New Api2PdfClient("YOUR_API_KEY")

Dim options = New HeadlessChromeOptions With {
    .HeaderHtml = "<div style='font-size:10px'>Company Header</div>",
    .FooterHtml = "<div style='font-size:10px'>Page <span class='pageNumber'></span></div>"
}

Dim response = Await a2pClient.HeadlessChrome.FromHtmlAsync(html, options)

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IronPDF Implementation:

using IronPdf;

var renderer = new ChromePdfRenderer();

// HTML headers and footers with full styling
renderer.RenderingOptions.HtmlHeader = new HtmlHeaderFooter
{
    HtmlFragment = "<div style='font-size:10px; text-align:center;'>Company Header</div>",
    DrawDividerLine = true
};

renderer.RenderingOptions.HtmlFooter = new HtmlHeaderFooter
{
    HtmlFragment = "<div style='font-size:10px; text-align:center;'>Page {page} of {total-pages}</div>",
    DrawDividerLine = true
};

var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("with-headers.pdf");

using IronPdf;

var renderer = new ChromePdfRenderer();

// HTML headers and footers with full styling
renderer.RenderingOptions.HtmlHeader = new HtmlHeaderFooter
{
    HtmlFragment = "<div style='font-size:10px; text-align:center;'>Company Header</div>",
    DrawDividerLine = true
};

renderer.RenderingOptions.HtmlFooter = new HtmlHeaderFooter
{
    HtmlFragment = "<div style='font-size:10px; text-align:center;'>Page {page} of {total-pages}</div>",
    DrawDividerLine = true
};

var pdf = renderer.RenderHtmlAsPdf(html);
pdf.SaveAs("with-headers.pdf");

Imports IronPdf

Dim renderer As New ChromePdfRenderer()

' HTML headers and footers with full styling
renderer.RenderingOptions.HtmlHeader = New HtmlHeaderFooter With {
    .HtmlFragment = "<div style='font-size:10px; text-align:center;'>Company Header</div>",
    .DrawDividerLine = True
}

renderer.RenderingOptions.HtmlFooter = New HtmlHeaderFooter With {
    .HtmlFragment = "<div style='font-size:10px; text-align:center;'>Page {page} of {total-pages}</div>",
    .DrawDividerLine = True
}

Dim pdf = renderer.RenderHtmlAsPdf(html)
pdf.SaveAs("with-headers.pdf")

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IronPDF supports placeholder tokens like {page} and {total-pages} for dynamic page numbering. For more options, see the headers and footers documentation.

ASP.NET Core Integration

Api2pdf's async HTTP pattern differs significantly from IronPDF's direct PDF generation.

Api2pdf Pattern:

[ApiController]
public class PdfController : ControllerBase
{
    private readonly Api2PdfClient _client;

    public PdfController()
    {
        _client = new Api2PdfClient("YOUR_API_KEY");
    }

    [HttpGet("generate")]
    public async Task<IActionResult> GeneratePdf()
    {
        var response = await _client.HeadlessChrome.FromHtmlAsync("<h1>Report</h1>");

        if (!response.Success)
            return BadRequest(response.Error);

        // Redirect to download URL
        return Redirect(response.Pdf);
    }
}

[ApiController]
public class PdfController : ControllerBase
{
    private readonly Api2PdfClient _client;

    public PdfController()
    {
        _client = new Api2PdfClient("YOUR_API_KEY");
    }

    [HttpGet("generate")]
    public async Task<IActionResult> GeneratePdf()
    {
        var response = await _client.HeadlessChrome.FromHtmlAsync("<h1>Report</h1>");

        if (!response.Success)
            return BadRequest(response.Error);

        // Redirect to download URL
        return Redirect(response.Pdf);
    }
}

Imports Microsoft.AspNetCore.Mvc

<ApiController>
Public Class PdfController
    Inherits ControllerBase

    Private ReadOnly _client As Api2PdfClient

    Public Sub New()
        _client = New Api2PdfClient("YOUR_API_KEY")
    End Sub

    <HttpGet("generate")>
    Public Async Function GeneratePdf() As Task(Of IActionResult)
        Dim response = Await _client.HeadlessChrome.FromHtmlAsync("<h1>Report</h1>")

        If Not response.Success Then
            Return BadRequest(response.Error)
        End If

        ' Redirect to download URL
        Return Redirect(response.Pdf)
    End Function
End Class

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IronPDF Pattern:

[ApiController]
public class PdfController : ControllerBase
{
    [HttpGet("generate")]
    public IActionResult GeneratePdf()
    {
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf("<h1>Report</h1>");

        // Return PDF directly - no download step needed
        return File(pdf.BinaryData, "application/pdf", "report.pdf");
    }

    [HttpGet("generate-async")]
    public async Task<IActionResult> GeneratePdfAsync()
    {
        var renderer = new ChromePdfRenderer();
        var pdf = await renderer.RenderHtmlAsPdfAsync("<h1>Report</h1>");

        return File(pdf.Stream, "application/pdf", "report.pdf");
    }
}

[ApiController]
public class PdfController : ControllerBase
{
    [HttpGet("generate")]
    public IActionResult GeneratePdf()
    {
        var renderer = new ChromePdfRenderer();
        var pdf = renderer.RenderHtmlAsPdf("<h1>Report</h1>");

        // Return PDF directly - no download step needed
        return File(pdf.BinaryData, "application/pdf", "report.pdf");
    }

    [HttpGet("generate-async")]
    public async Task<IActionResult> GeneratePdfAsync()
    {
        var renderer = new ChromePdfRenderer();
        var pdf = await renderer.RenderHtmlAsPdfAsync("<h1>Report</h1>");

        return File(pdf.Stream, "application/pdf", "report.pdf");
    }
}

Imports Microsoft.AspNetCore.Mvc
Imports System.Threading.Tasks

<ApiController>
Public Class PdfController
    Inherits ControllerBase

    <HttpGet("generate")>
    Public Function GeneratePdf() As IActionResult
        Dim renderer = New ChromePdfRenderer()
        Dim pdf = renderer.RenderHtmlAsPdf("<h1>Report</h1>")

        ' Return PDF directly - no download step needed
        Return File(pdf.BinaryData, "application/pdf", "report.pdf")
    End Function

    <HttpGet("generate-async")>
    Public Async Function GeneratePdfAsync() As Task(Of IActionResult)
        Dim renderer = New ChromePdfRenderer()
        Dim pdf = Await renderer.RenderHtmlAsPdfAsync("<h1>Report</h1>")

        Return File(pdf.Stream, "application/pdf", "report.pdf")
    End Function
End Class

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IronPDF returns the PDF directly via BinaryData or Stream, eliminating the redirect-to-download pattern.

Dependency Injection Configuration

// Program.cs or Startup.cs
public void ConfigureServices(IServiceCollection services)
{
    services.AddScoped<IPdfService, IronPdfService>();
}

// IPdfService.cs
public interface IPdfService
{
    PdfDocument GenerateFromHtml(string html);
    Task<PdfDocument> GenerateFromHtmlAsync(string html);
}

// IronPdfService.cs
public class IronPdfService : IPdfService
{
    private readonly ChromePdfRenderer _renderer;

    public IronPdfService()
    {
        _renderer = new ChromePdfRenderer();
        _renderer.RenderingOptions.PrintHtmlBackgrounds = true;
        _renderer.RenderingOptions.PaperSize = PdfPaperSize.A4;
    }

    public PdfDocument GenerateFromHtml(string html) =>
        _renderer.RenderHtmlAsPdf(html);

    public Task<PdfDocument> GenerateFromHtmlAsync(string html) =>
        _renderer.RenderHtmlAsPdfAsync(html);
}

// Program.cs or Startup.cs
public void ConfigureServices(IServiceCollection services)
{
    services.AddScoped<IPdfService, IronPdfService>();
}

// IPdfService.cs
public interface IPdfService
{
    PdfDocument GenerateFromHtml(string html);
    Task<PdfDocument> GenerateFromHtmlAsync(string html);
}

// IronPdfService.cs
public class IronPdfService : IPdfService
{
    private readonly ChromePdfRenderer _renderer;

    public IronPdfService()
    {
        _renderer = new ChromePdfRenderer();
        _renderer.RenderingOptions.PrintHtmlBackgrounds = true;
        _renderer.RenderingOptions.PaperSize = PdfPaperSize.A4;
    }

    public PdfDocument GenerateFromHtml(string html) =>
        _renderer.RenderHtmlAsPdf(html);

    public Task<PdfDocument> GenerateFromHtmlAsync(string html) =>
        _renderer.RenderHtmlAsPdfAsync(html);
}

' Program.vb or Startup.vb
Public Sub ConfigureServices(services As IServiceCollection)
    services.AddScoped(Of IPdfService, IronPdfService)()
End Sub

' IPdfService.vb
Public Interface IPdfService
    Function GenerateFromHtml(html As String) As PdfDocument
    Function GenerateFromHtmlAsync(html As String) As Task(Of PdfDocument)
End Interface

' IronPdfService.vb
Public Class IronPdfService
    Implements IPdfService

    Private ReadOnly _renderer As ChromePdfRenderer

    Public Sub New()
        _renderer = New ChromePdfRenderer()
        _renderer.RenderingOptions.PrintHtmlBackgrounds = True
        _renderer.RenderingOptions.PaperSize = PdfPaperSize.A4
    End Sub

    Public Function GenerateFromHtml(html As String) As PdfDocument Implements IPdfService.GenerateFromHtml
        Return _renderer.RenderHtmlAsPdf(html)
    End Function

    Public Function GenerateFromHtmlAsync(html As String) As Task(Of PdfDocument) Implements IPdfService.GenerateFromHtmlAsync
        Return _renderer.RenderHtmlAsPdfAsync(html)
    End Function
End Class

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Error Handling Migration

Api2pdf uses response object checks. IronPDF uses standard .NET exceptions.

Api2pdf Pattern:

var response = await a2pClient.HeadlessChrome.FromHtmlAsync(html);

if (!response.Success)
{
    Console.WriteLine($"Error: {response.Error}");
    return;
}

var response = await a2pClient.HeadlessChrome.FromHtmlAsync(html);

if (!response.Success)
{
    Console.WriteLine($"Error: {response.Error}");
    return;
}

Imports System

Dim response = Await a2pClient.HeadlessChrome.FromHtmlAsync(html)

If Not response.Success Then
    Console.WriteLine($"Error: {response.Error}")
    Return
End If

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IronPDF Pattern:

try
{
    var renderer = new ChromePdfRenderer();
    var pdf = renderer.RenderHtmlAsPdf(html);
    pdf.SaveAs("output.pdf");
}
catch (IronPdf.Exceptions.IronPdfLicenseException ex)
{
    Console.WriteLine($"License error: {ex.Message}");
}
catch (IronPdf.Exceptions.IronPdfRenderingException ex)
{
    Console.WriteLine($"Rendering error: {ex.Message}");
}
catch (Exception ex)
{
    Console.WriteLine($"Error: {ex.Message}");
}

try
{
    var renderer = new ChromePdfRenderer();
    var pdf = renderer.RenderHtmlAsPdf(html);
    pdf.SaveAs("output.pdf");
}
catch (IronPdf.Exceptions.IronPdfLicenseException ex)
{
    Console.WriteLine($"License error: {ex.Message}");
}
catch (IronPdf.Exceptions.IronPdfRenderingException ex)
{
    Console.WriteLine($"Rendering error: {ex.Message}");
}
catch (Exception ex)
{
    Console.WriteLine($"Error: {ex.Message}");
}

Imports IronPdf.Exceptions

Try
    Dim renderer = New ChromePdfRenderer()
    Dim pdf = renderer.RenderHtmlAsPdf(html)
    pdf.SaveAs("output.pdf")
Catch ex As IronPdfLicenseException
    Console.WriteLine($"License error: {ex.Message}")
Catch ex As IronPdfRenderingException
    Console.WriteLine($"Rendering error: {ex.Message}")
Catch ex As Exception
    Console.WriteLine($"Error: {ex.Message}")
End Try

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Performance Comparison

Metric	Api2pdf	IronPDF
Simple HTML	2-5 seconds (network)	100-500ms (local)
Complex page	5-10 seconds	500ms-2s
Batch of 100	Minutes (rate limits)	Seconds (parallel)
Offline	Not available	Works fully
Cold start	None	~2s (first render)

Performance Optimization Tips

// 1. Reuse renderer instance
private static readonly ChromePdfRenderer SharedRenderer = new ChromePdfRenderer();

public PdfDocument GeneratePdf(string html)
{
    return SharedRenderer.RenderHtmlAsPdf(html);
}

// 2. Parallel generation
var tasks = htmlDocs.Select(html =>
    Task.Run(() => SharedRenderer.RenderHtmlAsPdf(html)));
var results = await Task.WhenAll(tasks);

// 3. Disable unnecessary features for speed
var renderer = new ChromePdfRenderer();
renderer.RenderingOptions.EnableJavaScript = false; // If not needed
renderer.RenderingOptions.WaitFor.RenderDelay(0);   // No delay

// 1. Reuse renderer instance
private static readonly ChromePdfRenderer SharedRenderer = new ChromePdfRenderer();

public PdfDocument GeneratePdf(string html)
{
    return SharedRenderer.RenderHtmlAsPdf(html);
}

// 2. Parallel generation
var tasks = htmlDocs.Select(html =>
    Task.Run(() => SharedRenderer.RenderHtmlAsPdf(html)));
var results = await Task.WhenAll(tasks);

// 3. Disable unnecessary features for speed
var renderer = new ChromePdfRenderer();
renderer.RenderingOptions.EnableJavaScript = false; // If not needed
renderer.RenderingOptions.WaitFor.RenderDelay(0);   // No delay

Imports System.Threading.Tasks

' 1. Reuse renderer instance
Private Shared ReadOnly SharedRenderer As New ChromePdfRenderer()

Public Function GeneratePdf(html As String) As PdfDocument
    Return SharedRenderer.RenderHtmlAsPdf(html)
End Function

' 2. Parallel generation
Dim tasks = htmlDocs.Select(Function(html) Task.Run(Function() SharedRenderer.RenderHtmlAsPdf(html)))
Dim results = Await Task.WhenAll(tasks)

' 3. Disable unnecessary features for speed
Dim renderer As New ChromePdfRenderer()
renderer.RenderingOptions.EnableJavaScript = False ' If not needed
renderer.RenderingOptions.WaitFor.RenderDelay(0) ' No delay

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Troubleshooting Common Migration Issues

Issue: PDF Looks Different from Api2pdf Output

Match Api2pdf's Headless Chrome settings:

var renderer = new ChromePdfRenderer();
renderer.RenderingOptions.CssMediaType = PdfCssMediaType.Print;
renderer.RenderingOptions.PrintHtmlBackgrounds = true;
renderer.RenderingOptions.ViewPortWidth = 1280;
renderer.RenderingOptions.EnableJavaScript = true;
renderer.RenderingOptions.WaitFor.RenderDelay(1000);

var renderer = new ChromePdfRenderer();
renderer.RenderingOptions.CssMediaType = PdfCssMediaType.Print;
renderer.RenderingOptions.PrintHtmlBackgrounds = true;
renderer.RenderingOptions.ViewPortWidth = 1280;
renderer.RenderingOptions.EnableJavaScript = true;
renderer.RenderingOptions.WaitFor.RenderDelay(1000);

Dim renderer = New ChromePdfRenderer()
renderer.RenderingOptions.CssMediaType = PdfCssMediaType.Print
renderer.RenderingOptions.PrintHtmlBackgrounds = True
renderer.RenderingOptions.ViewPortWidth = 1280
renderer.RenderingOptions.EnableJavaScript = True
renderer.RenderingOptions.WaitFor.RenderDelay(1000)

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Issue: External Resources Not Loading

Configure resource loading timeouts:

var renderer = new ChromePdfRenderer();
renderer.RenderingOptions.WaitFor.AllFontsLoaded(timeout: 10000);
renderer.RenderingOptions.WaitFor.NetworkIdle(timeout: 10000);

// Or use base URL for relative paths
var pdf = renderer.RenderHtmlAsPdf(html, baseUrl: "https://example.com/");

var renderer = new ChromePdfRenderer();
renderer.RenderingOptions.WaitFor.AllFontsLoaded(timeout: 10000);
renderer.RenderingOptions.WaitFor.NetworkIdle(timeout: 10000);

// Or use base URL for relative paths
var pdf = renderer.RenderHtmlAsPdf(html, baseUrl: "https://example.com/");

Dim renderer = New ChromePdfRenderer()
renderer.RenderingOptions.WaitFor.AllFontsLoaded(timeout:=10000)
renderer.RenderingOptions.WaitFor.NetworkIdle(timeout:=10000)

' Or use base URL for relative paths
Dim pdf = renderer.RenderHtmlAsPdf(html, baseUrl:="https://example.com/")

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Issue: Large PDF File Sizes

Compress images after generation:

renderer.RenderingOptions.ImageQuality = 80;

// Or compress after generation
pdf.CompressImages(quality: 75);
pdf.SaveAs("compressed.pdf");

renderer.RenderingOptions.ImageQuality = 80;

// Or compress after generation
pdf.CompressImages(quality: 75);
pdf.SaveAs("compressed.pdf");

renderer.RenderingOptions.ImageQuality = 80

' Or compress after generation
pdf.CompressImages(quality:=75)
pdf.SaveAs("compressed.pdf")

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Post-Migration Checklist

After completing the code migration, verify the following:

Verify PDF output quality matches expectations
Test all edge cases (large documents, special characters)
Validate performance metrics (should see significant improvement)
Update Docker configurations if applicable
Remove Api2pdf portal account and API keys
Update monitoring (no more API latency tracking needed)
Document new patterns for your team
Update CI/CD pipelines

Future-Proofing Your PDF Infrastructure

With .NET 10 approaching and C# 14 introducing new language features, choosing a native .NET PDF library ensures compatibility with evolving runtime capabilities. IronPDF's commitment to supporting the latest .NET versions means your migration investment pays dividends as projects extend into 2025 and 2026—without ongoing per-conversion costs accumulating.

Additional Resources

Migrating from Api2pdf to IronPDF transforms your PDF generation from a cloud-dependent, per-conversion cost model to a local, one-time investment. Your sensitive documents stay on your infrastructure, latency drops from seconds to milliseconds, and you eliminate vendor dependency for this critical application capability.

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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How to Migrate from Api2pdf to IronPDF in C#

Why Consider Moving from Api2pdf?

Security and Compliance Concerns

Cost Accumulation Over Time

Performance and Availability

Api2pdf vs. IronPDF: Key Differences

Step-by-Step Migration Process

Step 1: Update NuGet Packages

Step 2: Update Namespace References

Step 3: Configure the License Key

Step 4: Remove API Key Configuration

Complete API Migration Reference

Core Class Mapping

Method Mapping

Rendering Options Mapping

Code Migration Examples

HTML to PDF Conversion

URL to PDF Conversion

HTML File to PDF with Options

Merging Multiple PDFs

Password-Protected PDFs

Headers and Footers

ASP.NET Core Integration

Dependency Injection Configuration

Error Handling Migration

Performance Comparison

Performance Optimization Tips

Troubleshooting Common Migration Issues

Issue: PDF Looks Different from Api2pdf Output

Issue: External Resources Not Loading

Issue: Large PDF File Sizes

Post-Migration Checklist

Future-Proofing Your PDF Infrastructure

Additional Resources

Start Free 30 Day Trial

How to Migrate from Api2pdf to IronPDF in C#

Why Consider Moving from Api2pdf?

Security and Compliance Concerns

Cost Accumulation Over Time

Performance and Availability

Api2pdf vs. IronPDF: Key Differences

Step-by-Step Migration Process

Step 1: Update NuGet Packages

Step 2: Update Namespace References

Step 3: Configure the License Key

Step 4: Remove API Key Configuration

Complete API Migration Reference

Core Class Mapping

Method Mapping

Rendering Options Mapping

Code Migration Examples

HTML to PDF Conversion

URL to PDF Conversion

HTML File to PDF with Options

Merging Multiple PDFs

Password-Protected PDFs

Headers and Footers

ASP.NET Core Integration

Dependency Injection Configuration

Error Handling Migration

Performance Comparison

Performance Optimization Tips

Troubleshooting Common Migration Issues

Issue: PDF Looks Different from Api2pdf Output

Issue: External Resources Not Loading

Issue: Large PDF File Sizes

Post-Migration Checklist

Future-Proofing Your PDF Infrastructure

Additional Resources

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