Do you issue your own invoices? Six routes to e-invoicing from January 2027

Receiving first, issuing second

Before deciding how you will issue invoices, you must have receiving in place – that is an obligation for every business regardless of VAT registration. For clients whose accounts we keep, we will arrange receiving of e-invoices via the KROS digital postman (clients whose accounts are kept in OMEGA) or STORMWARE (clients whose accounts are kept in POHODA), regardless of what you issue invoices in. Remember that a company may have only one postman for receiving but several for sending – issuing is therefore not tied to the postman we use.

Six ways to issue e-invoices

Listed from the most automated to the simplest. There is no single right answer – it depends on invoice volume, customer type, existing software and willingness to invest.

1. Upgrade your own software

Ask your software vendor whether and when it will enable e-invoice generation (XML per EN 16931) and a connection to a digital postman. The tax authority publishes the planned go-live dates of most Slovak vendors at www.info-efaktura.sk – most indicate the second half of 2026. For custom or legacy systems (bespoke ERP, EDI) your IT supplier will need to adapt the system or convert the data to the prescribed format and connect it to a postman via its interface. Suitable for companies with higher invoice volumes and an established system; budget for the modification costs and time for testing.

2. The invoicing tool of our accounting software – KROS (OMEGA, KROS Invoicing) or STORMWARE (POHODA, mPohoda)

We keep our clients’ accounts in two programs in parallel – OMEGA from KROS and POHODA from STORMWARE. Both developers are accredited digital postmen and have e-invoicing built directly into their invoicing tools. The simplest route for a client who wants to issue invoices personally is therefore to use the invoicing tool of the developer whose software we keep their accounts in: clients on OMEGA use the online KROS Invoicing app (KROS postman included, up to 50 e-invoices per month free of charge, live according to the tax authority from September 2026); clients on POHODA use POHODA itself or the mPohoda mobile app (STORMWARE postman with its own access point, sending and receiving up to a higher limit included in the SERVIS service or subscription, live since June 2026). In both cases we are invited into your invoicing tool as a user and take the issued documents straight into the accounts – no handing over of details, no retyping, and the data remains yours. If you currently invoice in another tool, we will prepare the switch for you, including transferring your customer list.

3. Another online invoicing app with a built-in postman

For small and medium volumes you may also use another app with e-invoicing and a postman built in – e.g. Doklado, SuperFaktura, Fakturix or ePodateľňa24 (the tax authority keeps the current list at www.info-efaktura.sk). You issue the invoice as before; the app sends it via Peppol and reports the data. Monthly costs range from zero to low tens of euros. The disadvantage compared with option 2 is that the documents do not reach our accounts automatically – a hand-over method has to be agreed with us (XML export, shared folder, access to the app).

4. Manual sending via the postman’s web interface

If you issue only a handful of invoices a month, you can create the invoice in your existing program and either export it as XML (if the program allows) or fill it in directly in the digital postman’s online form and send it manually. This is the cheapest but most laborious option, with a higher risk of errors and no automatic link to the accounts. We recommend it only as a temporary bridge or for a few invoices a year.

5. Invoicing by our office

For an agreed fee we take over issuing your invoices in OMEGA or POHODA: you send us the details (to whom, what, amount, date of supply), we issue the invoice, send it via the postman, ensure the data is reported to the tax authority and provide you with a PDF and XML view for your customers. The invoice is posted and archived immediately at the same time. Suitable for clients who do not want to invest in software and invoice in regular, manageable volumes. It requires discipline in handing over details – the 15-day deadline for issuing an invoice is statutory.

6. A combined solution

For larger companies it makes sense to split invoicing: keep bulk B2B invoices in your own system connected to a postman, continue to issue consumer invoices as PDF, and route exceptional or corrective documents through us. Where the customer issues the invoice in a supplier relationship (self-billing), a written agreement remains possible – the customer then issues and sends the e-invoice from its own system.

How to choose

What applies whichever option you choose

• Before the first live e-invoice, check your customers’ tax IDs, VAT IDs and addresses – a missing or incorrect tax ID means the invoice will not be generated.

• Test sending in the voluntary regime during 2026, ideally with a partner who already has a postman.

• Agree with us how issued documents will reach the accounts (XML export, invitation to the app, shared folder) – the aim is zero retyping.

• Retain the XML invoices for ten years – even if a third-party app issues them, the archiving responsibility is yours.

Sources: Finančná správa SR (Slovak tax authority) – www.info-efaktura.sk (list of postmen and software vendors’ dates), Frequently asked questions on e-invoicing 9/DPH/2025/IM (26 August 2026); KROS a. s. – www.kros.sk/efaktura; STORMWARE s. r. o. – www.stormware.sk/e-fakturacia/peppol; Act No. 222/2004 Coll. on VAT as amended by Act No. 385/2025 Coll. The apps mentioned are examples from the tax authority’s list, not a recommendation of any specific product. This article is for information purposes only and does not replace individual tax advice.