Definition

Electronic billing, or electronic invoicing refers to the digital transmission of an invoice, typically a file, from a sender computer to a recipient computer. This can e.g. be a XML file by email, a PDF download from a web portal, but it can also be a computer fax between two computers. If a dedicated protocol for the transmission of electronic invoices is used, it is still an electronic invoice, even a structured one, but more narrowly this is already called Electronic data interchange. In that particular case (of EDI) you might not even see a file.

Electronic invoices does not automatically mean you also have to pay electronically, however, the recipient can still pay how (s)he likes, e.g. in cash. It is under your responsability to pay the invoice, but at least structured and hybrid electronic invoices will state very clearly what has to be paid when to whom under which reference, so your banking software could technically present you a "balance this invoice" button.

Structured vs unstructured

Unstructured invoices are human readable, e.g. the image file of a scanned paper invoice. PDF files may contain a text layer, which can be used for OCR data if it is a scan. But even if this text may allow for copy&paste the precise meaning of the amounts are not defined in a machine readable way, both PDF files with and without text layers are still unstructured: a software would have to guess the meaning of a particular amount or a user would have to at least manually approve according assignments.

The meaning in a structured electronic invoice is usually expressed in a XML syntax: XML invoices are usually structured invoices. It defines data and meaning but it does not define a layout.

Structured electronic invoices are already obligatory for B2G invoices in some countries and will become also mandatory in germany.

Structured invoices can by hybrid or native.

Hybrid vs native

A invoice XML file, carrying the meaning of all items and attributes is typically a native structured electronic invoice: it does not carry layout information how to optically display it. So the layout of a print is not defined, the recipient would have to define that e.g. the total amount is to be displayed at the bottom right of the document. There are many native formats and versions, UNCEFACT CII and UBL are just two examples and there is a very nice comparison between UBL and UN/CEFACT available.

These formats require specialized reader software (standalone or integrated in your ERP ) capable of understanding it and presenting it to the user: You can automatically check the calculation but for the correctness, also native e-invoices usually have to be manually approved.

Since special reader software is required, native e-invoices are usually only accepted after a prior written agreement between the sender and recipient, agreeing on which precise format is delivered how by the sender.

Hybrid e-invoices define both meaning and layout. ZUGFeRD defines the invoice layout in a conventional PDF file, so you can use any PDF reader to access the invoice. The meaning (which amount is which tax amount and so forth), is additionally defined in a XML file which is embedded into the PDF file.

Since PDF readers are widely available, the recipient of the invoice can use=pay, the amount stated in the XML if (s)he has a suitable specialized reader or ZUGFeRD capability integrated into her ERP system. If that is not the case, one has to fallback to the human readable PDF version, which has to contain identical values. For hybrid invoices, there is usually no need for a agreement before exchanging invoices: if the recipient pays the invoice (s)he accepts it.

The FeRD published Guidelines for companies regarding electronic invoices. And E.ON Energie Deutschland GmbH produced a very basic (german) explanatory film on hybrid B2C e-invoices by :

Pro hybrid

Contra hybrid

Use cases

Have magic scans (hybrid only)
Some service providers scan paper invoices for their customers and delivers them as PDF. Since anyway already a optical character recognition (ORC) was run on the scans, they now also offer the service of semi-automatic invoice recognition and add manually corrected (and therefore guaranteed) ZUGFeRD metadata to their scans so that they can be automatically processed.
Facilitate Procure-To-Pay (hybrid and native)
When companies use ERP systems where
  • orders are entered into the system and
  • the storage facility registers every delivered item upon arrival in the system and
  • the invoice arrives as ZUGFeRD and refers to the order
The invoice can be automatically checked vis á vis the order and can be automatically payed and booked as envisaged when creating the order.
Have your suppliers in line (hybrid and native)
Some bigger companies have managed to persuade a significant amount of their suppliers to send ZUGFeRD invoices. This way he saves money because no paper or unstructured PDF invoices need to be processed.
Pay invoice files (hybrid and native)
ZUGFeRD means no more need to copy&paste IBAN, amount or purpose field for a bank transfer, it's sufficient to select the ZUGFeRD-PDF file to be paid. E.g. there is a proof of concept plugin for the open source onlinebanking software Hibiscus or a commercial product called CIB SEPArator which converts ZUGFeRD files to SEPA XML.

European Situation

B2G

Some countries introduced mandatory electronic invoices in the B2G sector, Denmark was the first in 2005, followed by Sweden 2008, Spain and Finland 2010 and Austria and Italy 2014.

Probaly also because already in 2009, Denmark could credibly explain that the e-invoice saves them 100 million Eur/year, in 2014, the EU decided in their 2014/55 EU Guideline to make electronic invoices for many B2G invoices mandatory for all member states.

The EU legislation ignores unstructured electronic invoices and defines electronic invoices as "an invoice that has been issued, transmitted and received in a structured electronic format". This -potentially strategic- omission has caused some confusion, since according to a german article, 68% of the participants in a survey (the article probably refers to this. thought differently.

The CEN has published EN16931 for this purpose which you can buy from your national standard body .

The non-EU but EFTA member Switzerland followed with electronic invoices in 2016. Germany will start accepting electronic invoices as of November 2018 and make it compulsory as of November 2020 on a federal level.

B2B

Electronic invoicing is voluntarily in the B2B sector.

In Austria, e-invoices are more or less treated like digital versions of the printed invoices, which makes it very easy to handle with. Austrian companies might even be allowed to destroy paper receipts after scans.

In Hungary, apparently e-invoices have to be digitally signed.

Regarding Switzerland, in 2018 Simone Sporing held a (german) speech "Die E-Rechnung in Industrie und Handel" how Coop introduced ZUGFeRD and that and how it was certified by the authorities Slides

For all details on all countries please refer to the "EU compendium on e-invoicing retention" which alsolists the legal requirements for the different countries and the (german) collection on legal foundations for electronic invoices in the EU (Sammlung der Rechtsgrundlagen für elektronische Rechnungen in der EG) and in particular interesting regarding B2G the CEFDIGITAL E-invoicing situation per country

Screenshot of the CEF Monitoring Dashboard
CEF Monitoring Dashboard showing a e-invocing "readiness factor" of the european countries

German Situation

B2G

As defined in the german e-invoice law (amended E-Rechnungsgesetz in Bgbl 19/2017) and the according act, the E-Rechnungsverordnung, structured e-invoices will become mandatory vis á vis the authorities as of November 2020 in germany.

All european formats providing the accordings attributes are allowed but the first german "country version" (i.e. CIUS) was the XRechnung. ZUGFeRD's CIUS are still in the draft state.

Early 2018, Mr. Hauschild summarized in a german speech the situation in german non-federal administration, namely german states and counties (slides) and recommended a german handbook for the authorities.

According to the justification for the e-Rechnungsverordnung the authorities receive an annual total of 7.95 million invoices, of which they expects 80% (6.36 million invoices) to become electronical.

The justification refers to the Architekturkonzept e-Rechnung, which estimates (page 96) 8 million invoices, half of which are direct and the other half are vis á vis the administration. Other sources talk about an expected 300,000 directly affected suppliers.

The official justification further expects a reduction of the processing time from 22,6 minutes to 11,78 minutes each and total savings of up to 62.38 million Euro for the government along with savings of 10.87 million Euro for the industry. The costs are expected to amount to 6.1 million Euro as a one off investment and 1.125 million Euro annually.

These 62.38 million is quite a lot but still much less than the 500 million expected in e.g. the Billentis E-invoicing business case, whichs says (page 21), "The difference to the total “public sector saving potential” above [in that case 6500-2600-3400] is the saving potential for the federal administration."). The business cases also mentions a total "Minimum public sector saving potential" of 6.5 billion Euro per year just for germany.

B2B

The german GOBD impose some obligations if you "save" an invoice in „the file-system“ - or if you accept (i.e. pay) structured or unstructured electronic invoices.

Among the most important duties is that both sender and recipient have to electronically archive the document in an unalterable way ("revisionssicher"), which requires (among others) tamper-free storage and a documentation of the process. BITKOMs has summarized the 10 most important requirements (german) and also published a exhausitive list of requirements vis á vis document management systems (in german).

On Youtube you will find a 20 minute german speech on electronic invoices for SME.

In general, scanned paper invoices may be disposed, but only after certain criteria are met: e.g. it is defined who is responsible for that particular scan, the according person checked that its complete and legible, and the first digital backup has been created.

There is a (german) sample documentation on how to scan and how to file (also german). The DATEV has confirmed (in german) that digital files can be legally compliant.

For unstructured and hybrid electronic invoices there is no legal requirement to ask the recipient for permission to send her electronic invoices, if the invoice is accepted and paid, it means the the recipient also complies to the additional regulations. It is, however, her right to reject the electronic version and explicitly ask for a paper copy. In this case the paper original probably has to be provided without additional cost.

History

ZUGFeRD

ZUGFeRD ( Zentraler User Guide Forum elektronische Rechnung Deutschland ) is a open european standart for a structured, hybrid PDF e-invoice . Technically, this works by embedding a XML file into PDF file. Embedded ZUGFeRD files work with all PDF readers but of course these readers may not automatically process the metadata.

Screenshot of Acrobat Adobe PDF Reader showing a ZUGFeRD invoice with open file attachments tab
At the right you see a sample PDF containing ZUGFeRD metadata generated with the Mustang library. If you open it in Adobe Acrobat Reader just click on the paperclip symbol to see the embedded ZUGFeRD XML structure.

Architecture

ZUGFeRD is based on

The PDF used in ZUGFeRD is PDF/A-3. PDF/A is a subset of PDF which does not only allow validation (PDF per se can not be validated), it is specifically designed for better archival: e.g. external fonts are always embedded in PDF/A. PDF/A-3 (standardized in ISO 19005-3:2012 and not at all related to the paper format DIN-A3) is the third version of the archivable PDF/A edition, which supports embedded files.

The CEN semantic model of a core invoice is already foundation for ZUGFeRD 1.0. It e.g. defines the correct number of decimals (rule 9): in quantity (4) , currency prices (4) and totals (2), the units and how the invoice amount is calculated.

Factur/X

Factur-X is just another name for ZUGFeRD 2.0.

Versions

ZUGFeRD 1.0 was relased

ZUGFeRD 2.0 is not yet officially released, but the (german) public preview has already been approved.

Changes towards ZUGFeRD 2:

  1. ZUGFeRD 2 is expected to support European B2G invoices, namely EN16931. Alternatively to ZUGFeRD (more precisely UN/CEFACT CrossIndustryInvoice D16B SCRDM uncoupled), UBL 2.1 and EDIFACT are also eligible for EN16931.
  2. ZUGFeRD 2 has been adopted by the french FNFE as "Factur-X version 1.0".
  3. In particular to accommodate french requirements there are two new profiles below basic,
    • Minimum
    • Basic Without Lines (BASIC WL)
    The profile Comfort has been renamed to EN 16931.
  4. The filename of the embedded file changes from ZUGFeRD-invoice.xml to factur-x.xml
  5. The XML part of ZUGFeRD 1 was some sort of a customized XML format based on UN/CEFACT. ZF2 is based on the original version of the XML schema, UN/CEFACTS Cross Industry Invoice CII, more precisely on UN/CEFACT CII SCRDM 16B uncoupled .
  6. The root node therefore changes from CrossIndustryDocument to CrossIndustryInvoice.
  7. The schema change also means that some elements are renamed, e.g.
    Name in ZF1 in ZF2
    SpecifiedExchangedDocumentContext ExchangedDocumentContext
    HeaderExchangedDocument ExchangedDocument
    ApplicablePercent ram:RateApplicablePercent
    SpecifiedSupplyChainTradeDelivery ram:SpecifiedLineTradeDelivery
    SpecifiedLineTradeAgreement ram:AssociatedDocumentLineDocument
    SpecifiedSupplyChainTradeAgreement ram:SpecifiedLineTradeAgreement
  8. some element names became more specific, e.g. ID became IssuerAssignedID if it was used in BuyerOrderReferencedDocument, DeliveryNoteReferencedDocument, AdditionalReferencedDocument or ContractReferencedDocument
  9. Now also the sequence of some elements is defined more specifically, which may cause you to reorder some elements, e.g. in SpecifiedSupplyChainTradeTransaction the IncludedSupplyChainTradeLineItem now has to be the first child BuyerOrderReferencedDocument, DeliveryNoteReferencedDocument, AdditionalReferencedDocument ContractReferencedDocument now have to start with ID, then typecode and some more.

You can use the commandline or Have a look at Mustangprojects (not very complete) XSLT file which facilitates the transformation from ZUGFeRD 1 XML to ZUGFeRD 2 XML.

Profiles

ZUGFeRD supports five different levels of required structured information Mustangproject complies to the Extended level.

XRechnung

The XRechnung is a native electronic invoice format which can be expressed in either UBL or UN/CEFACT XML. A UN/CEFACT XRechnung (like this one) is based on the same schema files, and thus extremely similar to the file embedded in a ZUGFeRD PDF.
Name Release date File format Hybrid B2G B2B with agreements B2B without agreements B2C XML dialect
XRechnung 2017-05-10 .xml n y y n n UBL, UN/CEFACT CII
ZUGFeRD 1.0 2014-06-25 .pdf y n y y y UN/CEFACT CII
ZUGFeRD 2.0 not yet .pdf y y y y y UN/CEFACT CII
You can also refer to a german ZUGFeRD/XRechnung comparison.

Samples

Further reading

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