XML
A text file with labelled fields, such as an invoice amount. Your software makes it for another computer to read.
Why it matters: One broken label can stop the recipient from reading your file.
Invoice and file terms, explained
A confusing error message can delay your invoice. Find the field name and what to fix.
The basics
E-invoice
An invoice file that accounting software can read directly. A plain PDF does not provide the same structured fields.
Why it matters: Missing invoice data can delay processing and payment.
Error
A problem that breaks a rule checked by the tool.
Why it matters: Correct the named field and check the file again.
Warning
A message asking you to review something that may need attention.
Why it matters: Read the message before deciding whether the file is ready.
Validation
Checking a file against a set of rules.
Why it matters: Fix the reported problems before sending the file again.
XSD
A file that sets the rules for an XML file. It lists required fields and their order.
Why it matters: A missing field or wrong order can cause rejection.
Schema
The agreed structure of a file, like a form with fixed boxes.
Why it matters: Choose the right form before checking your file.
UBL and CII
Two ways to write the same invoice information in XML.
Why it matters: Choose the format your customer accepts.
Electronic invoices
Access Point
A service that connects an organisation to Peppol.
Why it matters: A file check does not confirm that delivery succeeded.
BG-xx
A numbered group of related invoice fields. BG-4, for example, groups the seller's details.
Why it matters: A missing group can mean several required details are absent.
BT-10
The buyer reference field in the European invoice standard. It helps the customer route your invoice.
Why it matters: A missing or wrong reference can delay the invoice.
BT-nn
A numbered field in the European invoice standard. For example, BT-10 holds the buyer reference.
Why it matters: Use the code to find the field that needs correction.
CII
A standard file format for invoices, used inside Factur-X too.
Why it matters: A file in the wrong format may not be readable by the recipient.
CIUS
Extra invoice requirements for a country or a particular use.
Why it matters: A file may pass general checks and still fail these extra rules.
EN 16931
The European standard for the information an electronic invoice must contain.
Why it matters: An invoice can have the right file structure and still miss required information.
Peppol
A network for exchanging business documents through connected service providers.
Why it matters: Ask the recipient which address and document format to use.
Schematron
Rules that check how values in a file fit together, such as invoice totals.
Why it matters: A correct file layout alone does not prove that the amounts agree.
UBL
A standard file format for invoices and other business documents.
Why it matters: Your customer's software must support the format you send.
Terms by country
ANAF
Romania's tax authority. It operates services used for tax documents.
Why it matters: Use the authority's messages to follow up a rejected submission.
FA(3)
The Polish invoice format used by KSeF. It defines the fields in your invoice file.
Why it matters: An export in a different format may be rejected.
Factur-X
An invoice with a readable PDF and an XML file inside. People read the PDF; software reads the XML.
Why it matters: Both parts need to describe the same invoice.
HR-CIUS
Croatia's additional requirements for electronic invoices.
Why it matters: A file can pass European checks and still miss Croatian requirements.
KPD
KPD is Croatia’s code for the kind of product or service.
Why it matters: The wrong code can describe a different product or service.
KSeF
Poland's national electronic invoice system.
Why it matters: A file that fails its checks needs correction before the process can continue.
Leitweg-ID
A routing reference used by German public bodies. It tells the system which buyer should receive the invoice.
Why it matters: A wrong reference can send your invoice to the wrong place or cause rejection.
NIP
A Polish tax identification number.
Why it matters: The wrong number can identify the wrong business.
OIB
OIB is Croatia’s identification number for a person or business.
Why it matters: The wrong number can identify the wrong person or business.
PDF/A
A PDF format intended for keeping documents over time.
Why it matters: An ordinary PDF may not meet the invoice format's requirements.
RO e-Factura
Romania's system for sending and receiving electronic invoices.
Why it matters: An invoice with missing required data may need to be corrected and sent again.
SPV
Romania's online tax account, used to access services from ANAF.
Why it matters: You may need it to send or retrieve tax documents.
UPO
An official receipt confirming receipt of an electronic document in Poland.
Why it matters: Keep the receipt to check what was received.
XRechnung
The German electronic invoice standard for public administration.
Why it matters: Missing required details can lead to a rejected invoice.
ZUGFeRD
The German name for the shared invoice format also known as Factur-X.
Why it matters: Check which version and level the recipient accepts.
How files are built
Attribute
Extra information inside an XML opening label, such as a currency code.
Why it matters: A missing value can leave an amount without its currency.
Element
A labelled part of an XML file, such as the invoice date.
Why it matters: A missing required part can stop the file check.
Encoding
The way a text file stores letters and symbols, such as UTF-8.
Why it matters: The wrong setting can make names unreadable or stop the file opening.
Namespace
An address that distinguishes one set of XML field names from another.
Why it matters: A wrong address can make a valid field look unknown.
Well-formed XML
XML with correctly written labels and a readable basic structure.
Why it matters: A broken closing label must be fixed before deeper checks can run.
Wildcard
A wildcard allows file fields whose names belong to an allowed group.
Why it matters: Extra fields can still need their own rules. An allowed name does not confirm correct contents.
Payments
camt
Bank messages used for account statements and transaction reports.
Why it matters: A file your software cannot read leaves transactions to match by hand.
IBAN
An international bank account number.
Why it matters: A typing mistake can block a payment or identify another account.
ISO 20022
The international standard behind many bank message formats.
Why it matters: The bank and your software need the same message type and version.
pain.001
An XML file used to ask a bank to make credit transfers.
Why it matters: Incorrect account details or amounts can prevent payment processing.
pain.008
An XML file used to ask a bank to collect direct debits.
Why it matters: Incorrect collection details can cause rejection or require correction.
SEPA
The common area and rules for euro transfers and direct debits.
Why it matters: Use the payment file and bank requirements that match your transaction.
UETR
UETR is a unique reference used to track a Swift payment.
Why it matters: The wrong reference makes a payment harder to trace.
Tax and audit files
CBAM
The EU mechanism for reporting emissions linked to certain imported goods.
Why it matters: Missing required import data can leave a report incomplete.
D406
Romania's declaration used to submit SAF-T accounting data.
Why it matters: Missing or inconsistent data can lead to errors when preparing the declaration.
DAC7
Rules for reporting certain platform sellers and their activity.
Why it matters: Missing seller details can leave the report incomplete.
DORA register
A list of agreements with outside providers of computer and communication services.
Why it matters: Missing or inconsistent entries can cause errors in a reporting file.
JPK
Poland's standard files for tax and accounting data.
Why it matters: A wrong file type or missing field can prevent processing.
SAF-T
A standard audit file containing accounting data for tax checks. Each country can set its own version.
Why it matters: The wrong country format can make an otherwise complete export unusable.
Taxonomy
A list of names and rules for information in a business report.
Why it matters: The wrong list can make a required figure appear missing.
VAT
A tax charged on goods and services. An invoice records its rate and amount.
Why it matters: A wrong rate or total can cause an invoice check to fail.
XBRL
A format that labels figures in business reports, such as revenue.
Why it matters: Wrong labels can change how a reported figure is understood.