Mandatory e-invoicing in Slovakia from 1 January 2027: questions and answers

From 1 January 2027, mandatory electronic invoicing will apply in Slovakia to domestic business-to-business transactions. In many cases, a PDF invoice sent by email will no longer be enough. Which transactions are affected, who must be able to receive e-invoices and how do you choose a digital postman? We have summarised the answers to the most frequent questions from the first part of our webinar eFaktúra v praxi (E-invoicing in practice).

What is changing

What counts as an e-invoice from 1 January 2027?

An e-invoice will no longer be a PDF attached to an email, but a structured document in XML format compliant with the European standard EN 16931. Its purpose is to allow invoice data to be read and processed automatically by the accounting systems of both the customer and the Financial Administration.

However, e-invoicing will apply only to selected transactions. For all others, the existing methods remain valid, whether PDF, paper or EDI solutions common, for example, in the automotive industry. Most companies will therefore combine several ways of issuing documents.

Why is Slovakia introducing e-invoicing now, when the ViDA directive only applies from 2030?

The EU’s ViDA (VAT in the Digital Age) directive, adopted in May 2025, introduces mandatory e-invoicing for cross-border transactions from 1 July 2030. At the same time, it allows Member States to introduce it voluntarily for domestic supplies as well.

Slovakia has taken this option. For roughly three and a half years, e-invoicing will cover only domestic transactions, with cross-border transactions added from July 2030. From the outset, the system has been designed to be consistent with what will later become mandatory across the EU.

Who is affected

When do I have to issue an e-invoice?

The obligation arises only when all three of the following conditions are met at the same time:

1. the supplier is a Slovak VAT payer registered under § 4, § 4b or § 4c of the VAT Act (i.e. a person established in Slovakia);
2. the customer is a Slovak taxable person with its registered office or residence in Slovakia, or a Slovak legal entity that is not a taxable person (for example, a civic association, church or non-profit organisation);
3. the transaction is a supply of goods or services with the place of supply in Slovakia.

If any of these conditions is not met, you continue to invoice as before. We therefore recommend reviewing your transaction types and customer list to determine where e-invoicing needs to be set up. Some accounting software already flags, when an invoice is being issued, whether it falls within the scope of e-invoicing.

When do I not have to issue an e-invoice?

An e-invoice is not mandatory, in particular, for:

• invoices to private individuals who are not entrepreneurs (B2C, for example e-shops);
• supplies to foreign taxable persons, intra-Community supplies and exports;
• supplies with the place of supply in another Member State where you are registered for VAT;
• customers who hold a Slovak VAT ID but are registered under § 5 (foreign entities not required to have a digital postman);
• VAT-exempt supplies, for example financial, insurance or healthcare services, or the rental of real estate;
• simplified invoices and receipts issued through the e-kasa online cash register system.

For exempt supplies, you may send an e-invoice voluntarily via the Peppol network if the customer is a taxable person.

Are there cases in which I must not issue an e-invoice?

Yes. The law prohibits e-invoices when invoicing the Slovak Information Service and Military Intelligence, and for supplies subject to the Act on Classified Information. The draft amendment to the VAT Act also adds the Ministry of Defence of the Slovak Republic to this list. In these cases, invoicing continues as before.

Do I have to be able to receive e-invoices even if I am not a VAT payer?

Yes. The obligation to receive e-invoices does not stem from VAT registration but from taxable person status. Every Slovak entrepreneur, as well as every legal entity that is not a taxable person, must therefore set up a digital postman for receiving documents.

The Financial Administration has begun assigning a tax identification number (DIČ) to legal entities that do not have one, as the DIČ serves as the identifier for delivering e-invoices.

How to send e-invoices

Do I have to send e-invoices via a digital postman?

Not necessarily, but it is the preferred method. The law requires you to be able to generate an XML file compliant with EN 16931 and deliver it in a way that the customer can read it. A digital postman is a certified delivery provider in the Peppol network that sends the invoice on your behalf. The Financial Administration publishes a list of these providers.

Companies that have been exchanging invoices via EDI or EDIFACT for years may continue to do so. However, they must ensure conversion to the EN 16931 format in line with the procedure set by the Financial Administration. An XML file attached to an email is not sufficient, as the customer is usually unable to read it.

It is also important to keep the difference in reporting in mind. Only invoices sent via a digital postman are automatically reported to the Financial Administration. At its training sessions, the Financial Administration has indicated that the use of other solutions may prompt it to carry out an inspection.

Do I need the customer’s consent to send e-invoices?

The customer’s consent is not required for e-invoices sent via a digital postman. For invoices outside the scope of e-invoicing that you send electronically, for example as a PDF, the recipient’s consent is still required.

How do I choose a digital postman?

Do not start by comparing price offers. First, look at which systems you issue invoices from and look for a solution that connects to them as easily as possible. Some accounting and ERP systems have a digital postman directly integrated. Only then select your postman in the application on the Financial Administration portal. Expressing interest is non-binding.

When choosing, keep in mind that:

• you can have only one postman for receiving, and the Financial Administration expects you to have selected it by December or January at the latest, otherwise you will be in breach of the VAT Act;
• you can have several postmen for sending, for example for different invoicing systems, and an additional postman may request the Peppol ID assigned when you selected your receiving postman;
• the list of certified postmen (more than 80) does not always match the selection application, and if you cannot find your postman there, contact them directly;
• the postman will have access to sensitive data, such as your pricing, so in addition to price, also consider its cybersecurity certifications.

Deadlines, tolerance and reporting

What is the deadline for issuing an e-invoice, and which issue date should I use?

The deadline remains 15 days from the supply of goods or services, or 15 days from the end of the month for summary invoices. Once e-invoicing is extended to cross-border transactions in 2030, it will be shortened to 10 days.

What is new is that, according to the Financial Administration’s interpretation, the issue date must match the date the invoice is sent to the digital postman. If you issue an invoice on the 12th but send it to the postman on the 15th, the issue date must be changed to the 15th. A mismatch will appear to the Financial Administration as an error, so set this step up directly in your system. An additional five-day period applies only to self-billing.

Will the Financial Administration impose penalties for errors from January?

Under the draft amendment to the VAT Act, currently in its second reading, a tolerance period is to apply from January to June 2027. During this period, the Financial Administration would not impose penalties for:

• a mismatch between the issue date and the date the invoice is sent to the postman;
• incorrectly completed mandatory fields in the XML invoice.

However, the tolerance period does not cover the selection of a receiving postman or the obligation to issue invoices in XML format and send them. The Financial Administration will penalise failure to meet these obligations.

Who reports invoice data to the Financial Administration?

Real-time reporting is handled for you by your digital postman. Your obligation ends once you send the invoice to the postman and receive a notification confirming its receipt. Invoices sent by other means or outside the scope of e-invoicing are not reported to the Financial Administration.

Want to know more?

In the next parts of the eFaktúra v praxi webinar, we cover penalties, corrective documents, the Peppol network and archiving. If you are working out which of your transactions are affected by e-invoicing or how to set up your systems, the experts at Forvis Mazars in Slovakia will be happy to help.