Rechnungsleser – open & validate e-invoices (XRechnung, ZUGFeRD)

Rechnungsleser turns an e-invoice file into a readable invoice. It opens XRechnung (UBL and CII), ZUGFeRD and Factur-X PDFs, Peppol BIS and other EN 16931 invoices, renders them with the official KoSIT visualisation, validates them offline against the official KoSIT and EN 16931 rules and puts sender, amount due, due date, account and the validation result at the top. A summary adds totals, bank details and buyer reference. In Gmail, an optional button on XML and PDF attachments opens the invoice straight in the viewer, without a download; Chrome asks once for access to mail.google.com when you turn it on. All of that is free, for any number of invoices, and so is saving as XML, standalone HTML or PDF. Pro (€29 one-time, VAT included in the EU and UK, 14-day free trial, money back within 14 days of purchase) adds a GiroCode payment QR for your banking app, a PDF validation report to send to the issuer, and CSV and JSON export, including one CSV for all open invoices. Privacy: invoices are processed on your device. No server, no upload, no account, no analytics. Outbound requests are the Pro license check at Polar.sh, which contains no invoice data, and, with the Gmail button on, the download of the clicked attachment from Google.