If you currently send invoices via email as PDF attachments, this is technically considered “electronic delivery,” but it is not an e-invoice as defined by the upcoming eFaktúra system. Starting January 1, 2027, electronic invoicing legislation will take effect, and e-invoices will be based on structured data, not on an image or PDF file.
Below is a practical explanation of what this means and what companies should take away from it right now.
Why an e-invoice isn’t a PDF
The Financial Administration states this clearly: an electronic invoice is not a “simple PDF file.” An e-invoice is a structured file in XML format that contains all required information (invoice number, dates, description of goods or services, amounts, customer information, etc.) in a way that makes them automatically readable and processable by computers —without the need for manual transcription.
A PDF is human-readable, but to a system it is often just an “image of text.” Although it can be processed using OCR or various parsers, it is still prone to errors. An XML e-invoice, on the other hand, is a “data package” that an accounting or invoicing system can directly read and process.
What Will Be Mandatory Starting January 1, 2027 (and What Won’t)
“Data-based” delivery via the eFaktúra ecosystem will be mandatory
E-invoices must be sent and received through a certified delivery service provider — a digital mail carrier—that ensures secure distribution between senders and recipients.
This provider can be used in various ways:
- through accounting/billing software,
- through a web application,
- or through the mobile app.
It will be mandatory to be able to receive e-invoices (for taxable persons)
Receiving e-invoices will be mandatory for legal entities and business owners who are taxable persons (examples: companies, sole proprietors, self-employed professionals, small-scale farmers, and property landlords).
According to the Financial Administration, in order to receive them, it will be necessary to have a certified digital mail provider under contract.
XML “readability” is also required
At the same time, the readability of the invoice in the XML BIS format must be ensured (i.e., it must be possible to display it clearly and unambiguously).
What this (probably) won’t mean
- That PDFs will disappear from the world entirely. PDFs may remain as a visual preview for humans, but the core of mandatory e-invoices is structured XML.
- That it is only “for large entities”—the obligation to accept payments applies to broadly defined taxable persons.
What standards are involved: Peppol + XML (BIS) + EN 16931
E-invoicing is based on the European delivery standard developed by OpenPeppol and on the Peppol BIS format, which is based on the European standard EN 16931.
In practical terms: the goal is for invoices to be able to “travel” securely between companies and systems across the market and to have a uniform data structure.
Important dates to note
- January 1, 2026: Effective Date of the Electronic Invoicing Legislation
- Second quarter of 2026: Voluntary implementation of eFaktúra available for companies and entrepreneurs
- January 1, 2027: Effective Date of the Electronic Invoicing Legislation
In other words: 2026 is the ideal year for preparation and testing to ensure a stress-free transition as of January 1, 2027.
What to Do Today: A Simple Plan
- Find out if your invoicing/accounting software will support eFaktúra
(and in what mode—integration vs. external application). - Find a digital mail service that meets your needs
- Plan your internal invoice processing workflow
: Who receives them, who approves them, what counts as “properly received,” what constitutes a complaint, and who handles matching them with purchase orders.
An e-invoice is not a PDF. It is a structured XML file designed for automated processing and is intended to be transmitted via certified delivery providers within the Peppol network/standard.
Starting January 1, 2027, it will be essential for businesses (taxable entities) to be able to receive e-invoices and to have the necessary tools and processes in place to do so.
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