E-invoicing, explained

What is an e-invoice?

An e-invoice is an invoice issued, sent and received as structured data, usually an XML file, that the recipient's software can read on its own. A PDF sent by email is an electronic invoice in the everyday sense, but it is not an e-invoice: a person still has to read it and type it into their accounting system.

Because every field (seller, buyer, VAT number, lines, VAT rates, totals, payment details) sits in a defined place, an e-invoice can be checked, booked, approved and paid automatically. That is why governments across the EU are making them mandatory between businesses.

E-invoicing vs fiscalization

The two are often confused, but they are separate obligations with different purposes:

• Fiscalization reports an invoice to the tax authority at the moment it is issued. The authority confirms it with a unique code that must appear on the invoice. In Slovenia this is FURS with the ZOI and EOR codes; in Croatia, the Tax Administration with ZKI and JIR.
• E-invoicing is about how the invoice itself travels from seller to buyer: as structured data over an exchange network rather than on paper or as a PDF.

One invoice can be subject to both. A good invoicing tool handles them in the same flow, so you never have to think about which rule applies.

Formats and standards

The EU defined a common semantic model for e-invoices, EN 16931, so that invoices from different countries carry the same information. Each country then uses one or more technical formats built on it:

• eSLOG 2.0, the Slovenian national XML format, compliant with EN 16931.
• UBL 2.1, an international XML format used for Croatian e-invoices.

You don't need to know any of this to use Paply: you fill in an ordinary invoice form and Paply produces the right format for the country.

Country guides

Serbia has its own national e-invoicing system with different rules from both. Support for Serbia is on Paply's roadmap for a later phase.

How Paply helps

Glossary

EN 16931

The European standard that defines what information an e-invoice must contain, so invoices can be read across borders.

eSLOG 2.0

The Slovenian XML e-invoice format, aligned with EN 16931.

UBL 2.1

Universal Business Language, an international XML format for business documents, used for Croatian e-invoices.

FURS

The Financial Administration of the Republic of Slovenia, which verifies invoices paid in cash or by card.

ZOI

Protective mark of the issuer (zaščitna oznaka izdajatelja), a code calculated when a Slovenian invoice is issued.

EOR

Unique invoice identifier (enkratna identifikacijska oznaka računa) returned by FURS once it confirms the invoice.

Porezna uprava

The Croatian Tax Administration, which fiscalizes Croatian invoices.

ZKI

Protective code of the issuer (zaštitni kod izdavatelja) calculated for every fiscalized Croatian invoice.

JIR

Unique invoice identifier (jedinstveni identifikator računa) returned by the Croatian Tax Administration.

OIB

The Croatian personal identification number used for both people and companies.

KPD

The Croatian classification of products and services, used to classify items on e-invoices.

UPN QR

The Slovenian payment QR code. Scanning it in a banking app fills in the amount, IBAN and reference.

HUB3

The Croatian payment slip standard, printed as a 2D barcode that banking apps can scan.

CAMT.053 / MT940

Bank statement file formats. Import one into Paply and payments are matched to invoices.

pain.001

The SEPA payment order file format. Paply creates one to pay several supplier bills at once in your online bank.

FAQ