Attachments

Pass files through attachments to embed source data, supporting documents, or invoice XML. Viewers with an attachment panel list them there. This example embeds a Factur-X XML file:

import { render } from "takumi-pdf";

const pdf = await render(invoice, {
  attachments: [
    {
      name: "factur-x.xml",
      data: xml,
      mimeType: "application/xml",
      description: "Factur-X invoice data",
      relationship: "alternative",
    },
  ],
});

¹ Two attachments cannot share a name.

² The next table lists the values.

³ Falls back to metadata.creationDate.

relationship takes one of these values.

¹ The default.

Electronic invoicesCopy Anchor Link

For a Factur-X or ZUGFeRD document, use PDF/A-3 and attach the invoice XML. Invoices covers the rest of the setup.

import { render } from "takumi-pdf";

const pdf = await render(invoice, {
  pdfa: "3b",
  metadata: { title: "Invoice 1042", creationDate: "2026-08-06" },
  attachments: [
    {
      name: "factur-x.xml",
      data: xml,
      mimeType: "application/xml",
      description: "Factur-X invoice data",
      relationship: "alternative",
    },
  ],
});

The PDF/A-3 levels require three fields on each attachment:

• mimeType
• description
• a modification date from modificationDate, or the metadata.creationDate fallback

TypeScript enforces mimeType and description under these levels. A missing date fails the render.

Levels that allow attachmentsCopy Anchor Link

¹ The PDF 2.0 option.