Country deep dive
Slovakia has been here before — a voluntary B2B framework was planned for 2022 and quietly shelved. This time the mandate is legislated with a firm date.
Slovakia introduces mandatory structured e-invoicing for business-to-government and government-to-government transactions through the IS EFA (Informačný Systém Elektronickej Fakturácie) platform, aligned with EN 16931 — the foundation the 2027 B2B mandate extends.
A voluntary B2B framework originally planned for January 2022 was postponed indefinitely, reflecting the genuine complexity of getting this right — worth remembering when reading today's confirmed dates.
Scheme 0245 (SG:DIC) is formalised for the 10-digit Slovak Tax Identification Number (DIČ), the identifier Slovak end users will register under on the Peppol network.
Businesses can voluntarily register to test structured e-invoicing and reporting ahead of the January 2027 mandate, using a decentralised Peppol-based "5-corner" model.
Structured e-invoicing and real-time reporting become mandatory for domestic B2B and B2G transactions between Slovak VAT taxpayers, using certified "Digital Postman" access points on a Peppol-based network.
Using only certified Digital Postman service providers for transmission and reception becomes a firm requirement — the educational grace period built into the first half of 2027 ends here.
The mandate extends to intra-EU B2B transactions and foreign entities with Slovak VAT registrations. The domestic "Kontrolný výkaz" (VAT control statement) and EU "súhrnný výkaz" (EC Sales List) are fully retired, and the invoice issuance deadline shortens from 15 to 10 days.
Slovakia hasn't published a national CIUS — it's relying on the base EN 16931 standard rather than adding a distinctly Slovak layer on top.
Unlike Romania's RO_CIUS or Croatia's HR-FISK, Slovakia is currently building on the plain European base standard — watch for a national CIUS to be defined as the rollout matures.
Use scheme 0245 when registering Slovak end users on the Peppol network — this is the identifier that resolves to a specific recipient's DIČ for routing purposes.
The FAQ document (9/DPH/2025) is explicit: an e-invoice is defined as a machine-readable structured XML file, full stop — nothing that merely looks like an invoice qualifies.
Sending the invoice through a Digital Postman within the deadline is what fulfils the issuance obligation — the clock is on transmission, not just generation.
The "5-corner" label matters here: Digital Postmen don't just move invoices between trading partners, they report the data to the tax authority in the same step.
This is a genuine architectural step beyond Belgium's or the UK's plain 4-corner models — the reporting leg is built into the same transmission, not a separate filing.
Don't confuse the two — B2G invoices to IS EFA use UBL 2.1 or CII D16B directly; B2B invoices move via accredited Digital Postmen over Peppol, with IS eFaktúra receiving the reported data.
Rejection by the recipient must be handled bilaterally between supplier and buyer — there's no reject function within the Peppol network itself for this purpose.
This lighter-touch email path applies specifically to B2G scenarios for foreign entities — B2B still requires a Digital Postman relationship once the 2027 mandate applies.
The 2026 voluntary phase exists specifically so businesses can iron out integration problems before the mandate has teeth.
Check compatibility with EN 16931 / UBL XML output and identify any necessary upgrades before the mandatory go-live.
Do this well ahead of 1 January 2027 — and be aware that from 1 July 2027, only certified Digital Postmen may be used at all.
Register voluntarily to pilot invoice submission, validation, and correction workflows before the mandate carries real consequences.
Make sure your 10-digit DIČ is correctly registered under the Slovak identifier scheme — this is what makes you routable on the network.
Since direct modification of a transmitted invoice isn't possible, make sure your team understands the credit-note-plus-reissue process before they need it under pressure.
Automate submission close to the tax point rather than batching — the deadline runs from the chargeable event, not from when someone gets around to generating the file.
Slovakia is explicitly taking an educational approach through the first half of 2027 — but the fines behind that grace period are real.