From 1 January 2027 every Slovak VAT payer must issue domestic business and public-sector invoices as structured XML under the EN 16931 standard, delivered through a certified provider. Every business, including non VAT payers, must be able to receive one. The voluntary phase opened in May 2026. Unreported invoice data carries a fine up to 10,000 euro.
I opened the 47 page e-invoicing FAQ published by the Slovak Financial Administration looking for one sentence: what does a company issuing five invoices a month actually have to do. It took longer than it should have. I'm Tair Khamitov, and at DevNova I own exactly the part that breaks here, wiring systems into each other. This article is that one sentence, expanded into steps.
Contents
1. The hype: what you hear from outside, and what is true
Since spring, business owners have been getting three kinds of message, and each one leads somewhere different. The first is an email from a software vendor: from January you will not be able to issue an invoice, buy the higher tier. The second is a line from the bookkeeper: this does not apply to you, you are not a VAT payer. The third circulates in Facebook business groups: the state will build an app, wait and do nothing.
The first message exaggerates. The second is dangerously half true. The third is simply wrong. In its press release of 7 April 2026 the Financial Administration wrote plainly that it will not build its own solution for issuing and receiving electronic invoices, and that these services will be supplied by the commercial market.
Meanwhile every conference and webinar leads with the word Peppol and follows it with the word integration. A small business owner walks out convinced a six month IT project is coming. For most of them it is not. For some of them it is, and telling the two groups apart takes about ten minutes.
What surprises people is not the duty to issue invoices. It is the duty to receive them.
2. What an e-invoice is, and what it is not
Under the European directive, an e-invoice is an invoice issued, sent and received in a structured XML format under the EN 16931 standard, in either the UBL or CII syntax, so that accounting software can process it automatically. The Slovak national rules sit on the Peppol BIS Billing 3.0 profile.
So a PDF emailed to the customer? NO. Nor a scanned sheet of paper. The Financial Administration puts it in one sentence: a PDF is only an image document, while an e-invoice is a structured XML file processed automatically. The difference is not whether the invoice is digital. The difference is whether a machine can read it without retyping.
Transport runs over the Peppol network, the European infrastructure for secure exchange of business documents that started life in public procurement. You do not join it directly. You contract a certified delivery service provider, called a digital postman in Slovakia, and it sends and receives on your behalf. The Peppol authority for Slovakia is the Financial Directorate of the Slovak Republic, which accredits providers and maintains the national rules.
- Format: XML under EN 16931, in UBL or CII syntax.
- Transport: the Peppol network through a certified digital postman.
- Recipient consent: not required when the e-invoice is mandatory. Required if you send it outside the delivery service, by email or over EDI.
- Archiving: ten years from the end of the calendar year the invoice relates to, kept as XML.
3. Who this hits, and who it will surprise
Two separate duties get blurred into one in most conversations. Issuing e-invoices applies to VAT payers on domestic supplies to other businesses and to the public sector. Receiving them applies to EVERY business entity, legal persons and taxable natural persons alike, which means sole traders who are not VAT payers, and also lawyers, architects, artists, private farmers and people renting out property.
| Your situation | Must issue e-invoices | Must receive e-invoices | From |
|---|---|---|---|
| VAT payer invoicing a company or the state, domestically | Yes | Yes | 1 Jan 2027 |
| You run a business but are not a VAT payer | No | Yes | 1 Jan 2027 |
| You sell to consumers only (B2C) | No, consumer sales are out of scope | Yes, for the invoices your suppliers send you | 1 Jan 2027 |
| Cross border supplies inside the EU | Not yet | Not yet | Planned from 1 Jul 2030 |
| Classified supplies and deliveries to the Slovak intelligence services | No, paper stays | No | Statutory exemption |
This table is not our measurement. It is a transcript of a state document: the Financial Directorate's e-invoicing FAQ, reference 9/DPH/2025/IM, version of 7 July 2026, 47 pages. I am saying so because you should know what you can verify yourself, and in how many minutes.
The practical consequence for a hairdresser who is not a VAT payer and serves ordinary customers: her invoicing does not change. But from 1 January 2027 she must be able to receive an electronic invoice for her phone, energy or rent, which means contracting a digital postman even though she will never issue a single e-invoice. That exact case appears as a worked example in the Financial Administration's own press release.
The law does not ask whether you own an accounting system. It asks whether you can receive XML.
4. The reality: a timeline that is already running
| Date | What happens |
|---|---|
| 1 Jan 2026 to 31 Dec 2026 | Transition period. An e-invoice may be issued and delivered voluntarily, provided your customer also has a digital postman. |
| May 2026 | The Financial Administration opened voluntary participation in the eFaktúra system. |
| 1 Jan 2027 | Issuing and receiving domestic B2B and B2G e-invoices becomes mandatory. |
| 1 Jan 2027 to 30 Jun 2030 | Invoice data is reported to the Financial Administration for invoices sent or received through the delivery service. |
| 1 Jul 2030 | Cross border e-invoicing inside the EU. The VAT control statement is abolished. |
The first row is the one that matters. The transition period does not open in December. It has been running since January 2026 and closes on 31 December 2026. Voluntary sign-up opened during May. As I write this, five months remain before the hard start, and the testing window narrows every week.
The year 2030 is not a typo. The cross border phase belongs to the European VAT in the Digital Age (ViDA) package, and the VAT control statement is due to disappear with it. That is the part which actually removes paperwork, three and a half years after the obligation arrives.
5. Deadlines and fines: what you actually pay for
The deadline for issuing an invoice does not change: fifteen days from the supply of goods or services. That is the one number most people already know, and it is correct.
The second number is new. Once your digital postman receives an invoice, you have five days to report its data to the Financial Administration. The reporting happens automatically through the postman, so you will not be filing anything by hand. If the data goes unreported, is reported incorrectly, or arrives after the deadline, the fine can reach 10,000 euro. For a repeated breach it can reach 100,000 euro.
Two exemptions are worth remembering, because they sound like legal padding and are not. If you make an obvious mistake and correct it immediately, no fine follows. And if you can demonstrate that your contracted digital postman failed and the data was reported without delay once the fault was fixed, no fine follows either. The second exemption is the reason you pick a postman on reliability and support, not on the lowest price per document.
The fine is not for a badly written invoice. It is for unreported data.
One more thing gets forgotten. E-invoices must be archived in their original XML format for ten years from the end of the calendar year they relate to. Not as a PDF printout in a shared drive. If your accounting system does not handle that for you, it is a separate line on the list.
6. What to set up now: an afternoon checklist
This fits into one afternoon and it saves your December. Work through it in this order.
- Find your row in the table above. A VAT payer invoicing businesses carries both duties. A non VAT payer carries only the duty to receive. The difference decides what you have to buy.
- Send your accounting software vendor one question. The Financial Administration recommends exactly this: check whether the solution will be able to issue e-invoices, receive them, and talk to a digital postman. Ask for an answer with a date on it, not a promise.
- Pick a digital postman. The list of certified delivery service providers and their intermediaries is published by the Financial Administration in the VPDS register and updated continuously. You choose, not the state.
- Test during the voluntary phase. The transition period ends on 31 December 2026. Your first live invoice in January is not a test, it is production.
- Look at where your invoices are actually born. If an e-shop, a booking system or a CRM generates them, the obligation reaches that system too, not only your bookkeeping.
- Settle the ten year XML archive. Either your system does it, or you solve it separately.
Step two is the interesting one right now, because the answers are cautious. STORMWARE writes about POHODA and mPOHODA that it is carefully preparing both products for the change, including its own access point. SuperFaktúra says it will automatically become your digital postman and that you will not need another service. Both statements are in the future tense. Neither gives a launch date, and a launch date is exactly what your plan needs.
Software vendors are promising. Almost nobody is giving a date in writing.
7. Wiring it into a website or e-shop: where it really hurts
Let me be straight about it: most small businesses do not need an integration. If you issue five invoices a month by hand, a digital postman's web or mobile app is enough, plus access for your bookkeeper. The Financial Administration says the same in its FAQ. At a few dozen invoices there is no need for an expensive automated system. I am not going to sell an integration to someone who does not need one.
The pain starts elsewhere. It starts when the invoice is not born in the accounting program but in an order on your website. An e-shop that today generates a PDF after payment and emails it will have to expose the same data in the EN 16931 structure and hand it to a postman. That is not a template change. It is a change to the order data model: party identifiers, units of measure, tax categories, references to credit notes.
How long it takes comes from the Financial Administration itself. If you use software already connected to the Peppol network, activation is immediate. For custom or complex solutions, integration can take several days to several weeks. That second sentence is why this article says now rather than in the autumn.
If you run a custom e-shop, this work lives in the same place as the payment gateway and invoice generation, in the e-commerce modules. If you are looking at digitalization more broadly, e-invoicing is one line on a longer list, and that list is written out in the piece on digitalizing a small business. And if this kind of dated obligation annoys you, you are not alone. The same logic applied to GPSR and product pages: whoever handled it early spent a fraction.
8. What it costs
Exact prices are still settling, because the market is forming. Two figures exist today and both come from the state. In its press release the Financial Administration notes that abroad the cost typically runs from 0.05 to 0.50 euro per invoice depending on volume, and that some solutions handle low volumes for free. In the FAQ it then assumes that a subscription to a simple digital postman app will not cost more than the EU average of 5 to 12 euro a month.
There is a free route too, but understand what it is. Together with the expert community, the state published an open source tool, zrobefakturu.sk, for creating and validating an e-invoice. The application itself states that it serves educational purposes only and is not intended for production use. It is a demonstration of the format, not an invoicing system.
The state gave you a standard, a register and a network. You buy the software on the market.
On the integration side this is ordinary development work, and we price it like everything else. Custom integrations and automation workflows start at 480 euro setup, e-commerce modules run from 480 euro up to 3,600 euro and above for a full checkout with stock and invoicing. The whole price list is public, with no "contact us for a quote".
9. The solution: how we wire e-invoicing at DevNova
I will say it plainly: we do not have dozens of delivered Peppol integrations behind us. Almost nobody in Slovakia does, the network is launching right now. What we do have behind us are years of wiring e-shops into payment gateways and invoicing systems, and e-invoicing is the same discipline with stricter validation.
Typically it would look like this. First we walk through where the invoice is born in your case: in the accounting program, in a web order, in the CRM, or in all three at once. Then we decide whether you need an integration at all or whether the postman's own app is enough, and that is a decision we can make in a single call. If an integration does make sense, we connect your system to the chosen digital postman's API, fill in the missing fields required by Peppol BIS Billing 3.0, push test invoices while the voluntary phase is still open, and settle the XML archive.
We ship websites and integrations on an eleven day cycle at a fixed price, and finished projects sit on /work. For larger jobs I bring people onto the project depending on what the work needs. If you want a concrete answer for your own stack, send a short brief. Tell me what you invoice in and where your orders come from. Two sentences are enough for an estimate.
One request to close the practical part. Do not panic buy a new accounting system before you ask your current vendor. Most of them will support this. They just have not shipped it yet.
Frequently asked questions (FAQ)
When exactly do I have to start, in 2026 or in 2027? The obligation applies from 1 January 2027. The transition period, however, runs from 1 January 2026 to 31 December 2026, and voluntary participation opened in May 2026. The sensible move is to test during 2026, because in January you are already live.
Does e-invoicing apply to businesses that are not VAT registered? Yes, but differently. Only VAT payers must issue e-invoices. From 1 January 2027 every legal person and every taxable person must be able to receive them, including sole traders, liberal professions, private farmers and landlords. So a non VAT payer still needs a contracted digital postman.
What is Peppol, and why did Slovakia not build its own format? Peppol is the European network for secure exchange of business documents between companies and public institutions, built on the EN 16931 standard. The Peppol authority for Slovakia is the Financial Directorate of the Slovak Republic. The practical reason: a shared format opens the road to cross border EU invoicing, which is planned from 2030.
Do I have to replace my accounting software, or is an add-on enough? In most cases an add-on or an update is enough. The order of operations is clear. Ask your current vendor first whether the product will issue e-invoices, receive them, and talk to a digital postman. Change software only when the answer is no.
How does an e-invoice connect to an e-shop or a company website? Through the digital postman's API. The e-shop has to expose order data in the EN 16931 structure rather than as a PDF. If your software is already on the Peppol network, the Financial Administration says activation is immediate. For custom builds, plan for several days to several weeks of work.
What happens if a company misses the 1 January 2027 deadline? Unreported, incorrect or late reported data carries a fine of up to 10,000 euro, and up to 100,000 euro for a repeated breach. No fine is imposed for an obvious mistake corrected immediately, or where you can demonstrate that your digital postman failed.
Can e-invoicing be introduced gradually, or does everything switch at once? Gradually. That is what the 2026 transition period is for: you may deliver an e-invoice voluntarily whenever your customer also has a digital postman. The recommended path is to start with receiving, then add issuing, then automate the source of the data.
Do I need my customer's consent for an e-invoice? When issuing an e-invoice is mandatory, the recipient's consent is not required. You need consent only when you send the electronic invoice outside the delivery service, for example by email or over EDI.
How long do I have to keep e-invoices? Ten years from the end of the calendar year the invoice relates to, in the original XML format. A PDF printout does not satisfy the archiving duty.
About the author
My name is Tair Khamitov and DevNova is my web studio in Bratislava. We build websites, e-shops and integrations for small and mid-sized businesses across Central Europe, so obligations like e-invoicing reach me from the technical side: where in the system the data is born, and what has to change for it to pass validation. I am not a tax adviser or a lawyer, and this text is an orientation overview built from primary sources, not advice. For your specific case, ask your accountant. Contact: b2b@devnova.eu · DevNova.
External sources
- Financial Administration of the Slovak Republic, eFaktúra section, the official hub for mandatory e-invoicing.
- E-invoicing FAQ 9/DPH/2025/IM (PDF, 47 pages, version of 7 July 2026), the source for deadlines, fines and scope.
- Financial Administration press release of 7 April 2026 (PDF), worked examples and the per invoice cost estimate.
- Register of certified delivery service providers (VPDS), the official list of digital postmen.
- info-efaktura.sk, a guide to electronic invoicing for each group of taxable persons.
- Act No. 385/2025 Coll., the VAT Act amendment that introduces electronic invoicing.
- Peppol BIS Billing 3.0, the technical specification of the format and its validation rules.
- European Commission, VAT in the Digital Age (ViDA), the European framework the Slovak timeline follows.
- zrobefakturu.sk, an open source demonstration of creating and validating an e-invoice (its authors state it is for educational use only).
- STORMWARE, Peppol in POHODA and mPOHODA, the vendor's statement about its planned access point.