PDF to PDF/A C#

Install

Add the official ConvertAPI client to your project.

.NET CLI

dotnet add package ConvertApi

Package Manager (Visual Studio)

Install-Package ConvertApi

Setup

Initialize the client once and point it to the v2 platform.

using ConvertApiDotNet;

var token = Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN") ?? "YOUR_API_TOKEN";
var convertApi = new ConvertApi(token);

// Target the v2 endpoint
ConvertApi.ApiBaseUri = "https://v2.convertapi.com";

Quick start — PDF → PDF/A (default PdfA2b)

Make a minimal call to convert a single PDF and save the output to disk.

var result = await convertApi.ConvertAsync("pdf", "pdfa",
    new ConvertApiFileParam("File", @"C:\docs\document.pdf")
);
await result.SaveFilesAsync(@"C:\out");

Choose a specific PDF/A version

Target the exact ISO profile your policy requires (e.g., PdfA4e, PdfA3b).

var result = await convertApi.ConvertAsync("pdf", "pdfa",
    new ConvertApiFileParam("File", @"C:\docs\document.pdf"),
    new ConvertApiParam("PdfaVersion", "PdfA4e")   // 1a/1b, 2a/2b/2u, 3a/3b/3u, 4/4e/4f
);
await result.SaveFilesAsync(@"C:\out");

Embed e-invoice (Factur-X 1.0) — PDF + XML

Pair your visual PDF with machine-readable XML for compliant e-invoicing (use PDF/A-3).

var result = await convertApi.ConvertAsync("pdf", "pdfa",
    new ConvertApiFileParam("File",  @"C:\docs\document.pdf"),
    new ConvertApiFileParam("InvoiceFile", @"C:\docs\invoice.xml"),
    new ConvertApiParam("PdfaVersion",  "PdfA3b"),
    new ConvertApiParam("InvoiceFormat","facturX")
);
await result.SaveFilesAsync(@"C:\out");

Embed e-invoice (ZUGFeRD 2.0) — PDF + XML

Swap the format to ZUGFeRD 2.0 while keeping the same PDF/A-3 pattern.

var result = await convertApi.ConvertAsync("pdf", "pdfa",
    new ConvertApiFileParam("File", @"C:\docs\document.pdf"),
    new ConvertApiFileParam("InvoiceFile", @"C:\docs\invoice.xml"),
    new ConvertApiParam("PdfaVersion",  "PdfA3b"),
    new ConvertApiParam("InvoiceFormat","zugferd2")
);
await result.SaveFilesAsync(@"C:\out");

Batch convert a folder (auto-embed XML when present)

Process entire directories at once; if a matching .xml exists, embed it as an invoice automatically.

var inputDir  = @"C:\docs\in";
var outputDir = @"C:\docs\out";
Directory.CreateDirectory(outputDir);

foreach (var pdf in Directory.EnumerateFiles(inputDir, "*.pdf"))
{
    var xml = Path.ChangeExtension(pdf, ".xml");
    ConvertApiResponse result;

    if (File.Exists(xml))
    {
        result = await convertApi.ConvertAsync("pdf", "pdfa",
            new ConvertApiFileParam("File", pdf),
            new ConvertApiFileParam("InvoiceFile", xml),
            new ConvertApiParam("PdfaVersion",  "PdfA3b"),
            new ConvertApiParam("InvoiceFormat","facturX")
        );
    }
    else
    {
        result = await convertApi.ConvertAsync("pdf", "pdfa",
            new ConvertApiFileParam("File", pdf)
        );
    }

    await result.SaveFilesAsync(outputDir);
}

Put it together (tiny console app)

Drop these calls into Main to verify your setup end-to-end.

public static async Task Main()
{
    var token = Environment.GetEnvironmentVariable("CONVERTAPI_TOKEN") ?? "YOUR_API_TOKEN";
    var convertApi = new ConvertApi(token);
    ConvertApi.ApiBaseUri = "https://v2.convertapi.com";

    await convertApi.ConvertAsync("pdf", "pdfa",
        new ConvertApiFileParam("File", @"C:\docs\document.pdf")
    ).Result.SaveFilesAsync(@"C:\out");

    await convertApi.ConvertAsync("pdf", "pdfa",
        new ConvertApiFileParam("File", @"C:\docs\document.pdf"),
        new ConvertApiParam("PdfaVersion", "PdfA4e")
    ).Result.SaveFilesAsync(@"C:\out");

    await convertApi.ConvertAsync("pdf", "pdfa",
        new ConvertApiFileParam("File", @"C:\docs\document.pdf"),
        new ConvertApiFileParam("InvoiceFile", @"C:\docs\invoice.xml"),
        new ConvertApiParam("PdfaVersion", "PdfA3b"),
        new ConvertApiParam("InvoiceFormat", "facturX")
    ).Result.SaveFilesAsync(@"C:\out");
}

Helpful notes

• Invoice params: Use InvoiceFile (XML) + InvoiceFormat (facturX, zugferd1, zugferd2) with a PDF/A-3 profile (PdfA3a, PdfA3b, or PdfA3u).
• Validation: Outputs are intended to be VeraPDF-validated for ISO conformance.
• Large jobs: Add retry logic or raise timeouts for very large documents.