E-invoicing in Slovakia from 2027: deadlines, Peppol and accredited providers

Slovakia adopted Act 385/2025 Z.z. on 9 December 2025: from 1 January 2027 e-invoicing becomes mandatory for B2B and B2G transactions, with voluntary use possible from May 2026. Instead of a central state platform, Slovakia chose the Peppol network with accredited service providers. Here is what that means in practice and how to make sure your invoices pass.

The deadlines

From May 2026: voluntary e-invoicing is possible.
From 2027-01-01: e-invoicing is mandatory for B2B and B2G transactions (Act 385/2025 Z.z., adopted 2025-12-09) – a plain PDF no longer counts as a valid invoice.
From July 2030: intra-EU cross-border transactions follow the EU ViDA rules.

Penalties for non-compliance reach up to €10,000 per infraction – so it pays to get the format right before 2027, not after.

How the Slovak model works

Slovakia uses a purely decentralised Peppol five-corner model, nicknamed the “Digital Postman”: invoices are exchanged over the Peppol network through accredited service providers, which at the same time report invoice data to the Financial Administration in near real time. The originally planned central platform IS EFA was cancelled; the first provider accreditations were published in January–March 2026.

This validator checks the format and the official Peppol rules; the transmission itself will require an accredited provider from 2027 – validation here, sending through your provider.

Format: EN 16931 / Peppol BIS 3.0

The law accepts invoices that follow the European standard EN 16931 in either UBL 2.1 or CII syntax – in practice Peppol BIS Billing 3.0 (UBL 2.1), which this validator covers. One format serves both Slovak domestic invoices and your other Peppol markets.

The Slovak party identifier in the Peppol network: schemeID 0245 (DIČ – the 10-digit tax identification number), mandated by the Slovak Peppol Authority for the 2027 registration. Both seller and buyer electronic addresses (EndpointID) are mandatory.

Errors that most often block invoices

Missing seller or buyer electronic address (PEPPOL-EN16931-R020 / R010).
Missing buyer reference or order reference (PEPPOL-EN16931-R003).
VAT identifier without the country prefix – SK2020123456, not 2020123456 (BR-CO-09).
Totals that do not add up to the cent – round each line first, then sum (BR-CO-10, BR-CO-13, BR-CO-15).
Empty XML elements, which the Peppol profile forbids (PEPPOL-EN16931-R008).

How to prepare

If you trade with Slovak partners, agree on Peppol addresses (EndpointID with schemeID 0245) and references before the deadline.
Verify that your software exports UBL 2.1 with the Peppol BIS Billing 3.0 profile.
Follow the accreditation of service providers – sending will go through them from 2027.
Test your files in the validator – every error is explained in plain language.