Downloading Invoices

Use direct download when you already know one KSeF number. Use exports when you need many invoices or want the SDK to download encrypted package parts.

Download one invoice

xml_bytes = auth.invoices.download_invoice(ksef_number="KSeF-number")

with open("invoice.xml", "wb") as handle:
    handle.write(xml_bytes)

If the invoice was just sent, poll until KSeF makes the processed XML downloadable:

xml_bytes = auth.invoices.wait_for_invoice_download(
    ksef_number="KSeF-number",
    timeout=120.0,
    poll_interval=2.0,
)

Export many invoices

Exports are asynchronous. Schedule an export from filters, wait for the package, then fetch decrypted ZIP parts.

Save files

export = auth.invoices.schedule_export(filters=filters)
package = auth.invoices.wait_for_export_package(
    reference_number=export.reference_number,
    timeout=300.0,
)

for path in auth.invoices.fetch_package(
    package=package,
    export=export,
    target_directory="downloads",
):
    print(path)

In memory

zip_parts = auth.invoices.export_and_download(
    filters=filters,
    timeout=300.0,
)

for part in zip_parts:
    print(len(part))

Encryption is handled by the SDK

Export packages are encrypted by KSeF. The high-level export helpers load a valid KSeF encryption certificate, schedule the export, download the package parts, and decrypt them before returning bytes or saved paths.

After sending invoices

If your workflow sends and then downloads invoices, keep the two phases separate:

1. Send XML through an online or batch session.

2. Persist the returned KSeF number or session reference.

3. Poll session status or metadata until processing completes.

4. Download by KSeF number, or build an export filter for the same period.

Next workflows

• Send invoices
• Query invoices
• Invoice retrieval API