> For the complete documentation index, see [llms.txt](https://api.qvalia.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://api.qvalia.io/qvalia-developer-tools/attachments-to-messages.md). # Attachments to messages Often our customers want to add, or request, attached documents to their messages, e.g. their invoices. **The total request must stay under 100 MB in total, as that is the current limit in the Peppol network!** {% hint style="warning" %} As attachments are base64-encoded inside the message, which increases the payload by about\ 33%, you must take care to use the proper size estimate, and not look at the original file size! {% endhint %} We support all the same attachments as Peppol does: [Peppol media types](https://docs.peppol.eu/poacc/billing/3.0/bis/#media-type) | SUPPORTED FILE TYPES | | | -------------------- | --------------------------------------------------------------------------------------------------------------------------- | | **Do**cuments | application/pdf | | Images | image/png image/jpeg | | Text | text/csv | | Spreadsheet |

application/vnd.openxmlformats-officedocument.spreadsheetml.sheet application/vnd.oasis.opendocument.spreadsheet

| ### Technical details Any attachment has to be `base64` encoded and added under the `AdditionalDocumentReference` element;
JSONXML
{
  "AdditionalDocumentReference": [
    {
      "ID": [
        {
          "_": "InvoiceSpecification01"
        }
      ],
      "DocumentType": [
        {
          "_": "Specification"
        }
      ],
      "Attachment": [
        {
          "EmbeddedDocumentBinaryObject": [
            {
              "_": "UjBsR09EbGhjZ0dTQUxNQUFBUUNBRU1tQ1p0dU1GUXhEUzhi",
              "mimeCode": "application/pdf",
              "filename": "InvoiceSpecification01.pdf"
            }
          ]
        }
      ]
    }
  ]
}

<cac:AdditionalDocumentReference>
  <cbc:ID>InvoiceSpecification01</cbc:ID>
  <cac:Attachment>
    <cbc:EmbeddedDocumentBinaryObject mimeCode="application/pdf" filename="InvoiceSpecification01.pdf">UjBsR09EbGhjZ0dTQUxNQUFBUUNBRU1tQ1p0dU1GUXhEUzhi</cbc:EmbeddedDocumentBinaryObject>
  </cac:Attachment>
</cac:AdditionalDocumentReference>


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