In brief
- From 1 January 2027 a VAT payer registered under § 4, § 4b or § 4c must issue invoices for domestic supplies to other businesses as e-invoices and send them over Peppol; the main exceptions are exempt supplies and simplified invoices.
- Every company and business a VAT payer invoices must be able to receive them — non-VAT-payers, sole traders and landlords included.
- The address is the tax number (0245:DIČ), not the company ID, and readiness should be checked in the network's address book (the SML), not only the Peppol Directory.
- A sender who sends through the delivery service has met its obligation even if the invoice fails — but an invoice that never arrived may well go unpaid.
From 1 January 2027 Slovak businesses change how they send each other invoices. A VAT payer can no longer email a customer a PDF: for domestic supplies it must issue an electronic invoice and deliver it over the Peppol network. Below is what matters — who, what, how the recipient is addressed, and how to check in advance that an invoice will arrive.
What an e-invoice is
An e-invoice is not a PDF. It is a structured XML file under the European standard EN 16931 (in UBL or CII syntax) that accounting software reads without retyping. It is sent through a certified delivery service provider — the Financial Administration calls it a Digital Postman — on the Peppol network.
Who must issue e-invoices
From 1 January 2027, every VAT payer registered under § 4, § 4b or § 4c of the Slovak VAT Act, for domestic supplies of goods and services to businesses and public bodies (B2B and B2G). Foreign payers registered under § 5 are not covered. 2026 is a transition year in which e-invoices may be sent voluntarily, if the customer has a Digital Postman too.
- Invoices to consumers (B2C) are out of scope.
- VAT-exempt supplies (§ 28 to 43 and 47 of the VAT Act), such as property rental without VAT, and simplified invoices — receipts up to €100 or eKasa receipts — are out of scope.
- Cross-border supplies are out of scope — according to the Financial Administration they are planned from 1 July 2030, together with the abolition of the VAT control statement.
- An e-invoice must not be issued to the Slovak Information Service, Military Intelligence, or for supplies involving classified information (§ 85o(2) of the VAT Act).
Who must be able to receive them
This is much wider. From 1 January 2027 every legal person and every taxable person that a VAT payer invoices must be able to receive an e-invoice — non-VAT-payers included. The Financial Administration names sole traders, liberal professions (lawyers, notaries, architects, artists), self-employed farmers and landlords. Even if they never issue one, they need a contract with a Digital Postman.
- Guide: Checking e-invoicing right in ChatGPT or Claude
- Guide: Getting ready to receive e-invoices step by step
The address is the tax number, not the company ID
On Peppol a Slovak company is addressed as 0245:DIČ — its ten-digit tax identification number under scheme 0245. Not its company ID (IČO) and not its VAT ID. In practice this is the first obstacle: accounting software and contracts work with IČO, the network wants DIČ.
A subject without a DIČ cannot receive an e-invoice. The Financial Administration advises applying for income tax registration in good time — a DIČ is issued within 30 days of the application.
What if the customer is not on the network
According to the Financial Administration, the sender has met its obligation once the invoice is sent through the delivery service — even if delivery fails because the customer never registered. The Financial Administration does not mention any duty to check the customer's readiness first.
So you are fine for tax purposes, but not commercially: an invoice that does not arrive does not get paid. You may also send the same e-invoice by another channel, such as email — the Financial Administration treats that as making an existing invoice available again, not as issuing a new one. That is why it pays to know in advance which customers are not ready, and to contact them in December.
Why the Peppol Directory is not enough
The Peppol Directory is a public, searchable list of network participants, but being listed in it is optional. The network's real address book is the SML (Service Metadata Locator) — that is what a Digital Postman consults to find where to deliver.
The difference is not small. On 17 September 2026 the Peppol Directory listed 922 Slovak participants, while by our sample-based estimate the network itself held about 2,100. As of 23 September 2026 we found 2,510 Slovak companies in the SML, out of roughly 650,000 subjects with a DIČ that the Financial Administration publishes. Checking the Directory alone can mark a ready customer as not ready.
Companies registered under another scheme
About 9% of Slovak entries in the Peppol Directory are registered under a scheme other than 0245 — mostly 9950, some even under their company ID. Such a company is on the network, but an invoice addressed by DIČ, as Slovak rules prescribe, will not reach it. If it is your customer, tell them — they can arrange a registration under their DIČ with their Digital Postman.
How to check
Our free tool finds the DIČ from a company ID, checks it against the network itself (the SML), tells you whether the company actually receives Peppol BIS Billing 3.0 invoices, flags a registration under another scheme, and shows whether the company is a VAT payer.
With dozens or hundreds of customers, check them at once through the API — up to 100 company IDs per request — and when one of them registers, see it in the change feed, by webhook or in the morning email.
Penalties
The penalties the Financial Administration's FAQ lists concern reporting invoice data: up to €10,000 for data not reported, reported wrongly or late, up to €100,000 for repeated breaches. The Digital Postman does the reporting for you; an obvious error corrected promptly is not penalised, nor is a provable failure of the Digital Postman, provided the data is reported promptly once the fault is fixed.