In the previous article we explained what an e-invoice is and who it applies to. Now we turn to the practical side. We distinguish two situations: a business that handles its own bookkeeping and invoicing, and a client whose accounts we keep in the OMEGA software from KROS.
E-invoicing in practice: what you must do yourself and what we will handle for you
Situation A: you have no accounting firm or tax adviser
If you keep your own books, or only use an invoicing app, the entire responsibility for the transition to e-invoicing rests with you. We recommend the following steps:
Find out what applies to you. Are you a VAT payer? Whom do you invoice – Slovak businesses, consumers, foreign customers? How many invoices do you issue and receive per month? This determines whether you need full invoicing software or whether a simple mailbox with a postman is enough (the tax authority estimates the cost of such a mailbox at EUR 5 to 12 per month).
Choose a digital postman. The register of certified providers is at vpds.financnasprava.sk; an overview of simple mailboxes for small businesses is also available at www.info-efaktura.sk. You may have only one postman for receiving invoices, and switching later is administratively demanding – choose with a horizon of several years.
Check your software. If you invoice from a program or app, ask the vendor when it will enable issuing and receiving e-invoices via Peppol and which postmen it is connected to. The tax authority publishes the planned go-live dates of individual vendors; most are scheduled for the second half of 2026.
Clean up your partner master data. Once sent, an e-invoice cannot be corrected, only cancelled by a corrective document. If your customer record contains a wrong company ID, tax ID or VAT ID, or an incomplete address, the invoice will not be generated at all. Check your own details, bank account and document numbering series as well.
Inform suppliers and customers of your Peppol ID and ask for theirs. Without the correct recipient identifier, the invoice cannot be delivered.
Arrange archiving. The XML e-invoice is a full-fledged tax and accounting document that you must retain in its original format for the entire retention period (generally 10 years). A printed PDF is not sufficient, and the postman does not take over this obligation.
Test it. Participation in 2026 is voluntary – use it to send test invoices before January 2027.
Situation B: you are our client and we keep your accounts in OMEGA
We process our clients’ accounts in the double-entry accounting software OMEGA from KROS. KROS is listed in the tax authority’s register as a digital postman (the service is provided in cooperation with its certified partner eConnect), and the e-invoicing function – including the Peppol connection and automatic data reporting to the Slovak tax authority (Finančná správa SR) – is to be available in OMEGA from autumn 2026. Receiving e-invoices in KROS is free and unlimited; issuing up to 50 e-invoices per month is included in the software licence.
For our clients this means that we will handle the technical side – generating the XML, sending it to the Peppol network, collecting received invoices and reporting data to the tax authority. The division of tasks looks like this:
| What we will handle | What we need from you |
|---|---|
| We will set up and configure the KROS digital postman for your company and link it to your accounts in OMEGA. | You confirm the choice of KROS as your digital postman by signing the contractual documentation or a power of attorney for our office. Reminder: you may have only one postman for receiving invoices. |
| We will import received e-invoices directly into the books – no retyping, scanning or forwarding e-mails. | Invoices that will continue to arrive as PDF or on paper (from non-VAT payers, from abroad, from consumers) should be sent to us as before, ideally on an ongoing basis. |
| If we issue invoices on your behalf, we will issue them as e-invoices in OMEGA, send them via Peppol and take care of data reporting within 15 days. | Send us the invoicing details (what, to whom, for how much, date of supply) immediately after the supply – the deadlines for issuing invoices and reporting data are statutory and subject to penalties. |
| If you issue invoices yourself in KROS Invoicing or in OMEGA, we will connect your invoicing to our accounting and download the documents automatically. | When issuing, you mark the document as an e-invoice and send it with a single click. If you use different invoicing software, we will agree on a way of handing over XML documents. |
| We will check and clean your partner database (company ID, tax ID, VAT ID, addresses) and document numbering series before January 2027. | You verify the Peppol identifiers of your key customers and suppliers and inform them of yours; together we update the invoicing clauses in your contracts. |
| We will set up archiving of XML e-invoices in line with the Accounting Act. | Responsibility for archiving remains with you by law as the accounting entity – we will agree where and how the documents are stored. |
| We will keep you informed about readiness and deadlines. | You respond to our questions in good time and inform us of changes (new software, new premises, change of VAT status). |
What to watch out for in either situation
E-invoicing does not remove errors in data, it exposes them – incomplete partner identifiers mean an invoice that is not sent. A sent e-invoice cannot be edited afterwards; every correction is a new corrective document, which is again reported to the tax authority. And finally: the state will have the data from your invoices within days, not months. Discrepancies between issued invoices, the VAT return and the control statement will be visible immediately.
Conclusion: what this means for your business
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Sources: Finančná správa SR (Slovak tax authority) – www.info-efaktura.sk, vpds.financnasprava.sk; KROS a. s. – www.kros.sk/efaktura, KROS Academy: Electronic invoicing from 1 January 2027; Act No. 385/2025 Coll. Information on OMEGA features is based on the vendor’s publicly announced plans as of September 2026. This article is for information purposes only and does not replace individual tax advice.
![[Translate to English:] Ing. Ján Polóny, PhD.](/fileadmin/_processed_/6/7/csm_polonyjan_358d7c569c.jpg "[Translate to English:] Ing. Ján Polóny, PhD.")