E-invoicing in Slovakia: mandatory B2B from 1 January 2027, 5-corner CTC on Peppol, BIS Billing 3.0 and TDD for domestic invoices only.
From 1 January 2027, Slovakia requires e-invoicing for domestic B2B and B2G transactions. The invoice goes to the buyer over Peppol. Only a domestic transaction (Slovakia to Slovakia) also sends a Tax Data Document (TDD SK) to Finančná správa, in parallel. The tax authority does not approve the invoice beforehand. The format is Peppol BIS Billing 3.0. Status towards the tax authority is MLS (Message Level Status).
During 2026, businesses can connect and test on a voluntary basis. The material duty starts on 1 January 2027.
The invoice goes from the supplier (C1) through two Access Points (C2 and C3) to the buyer (C4). On a domestic transaction, both Access Points send a TDD to Finančná správa (C5) in parallel. The invoice does not pass through C5, and C5 does not approve it in advance. MLS comes back from C5 to the Access Points.
A failure or delay at C5 must not stop delivery of the invoice. For the European context, see continuous reporting and CTC models.
On domestic traffic, the supplier files the reporting data at invoicing or within 15 days. The buyer reports receipt within 5 days.
BIS Billing 3.0 is the invoice format. OpenPeppol does not publish a PINT-SK. TDD SK version 1.0.0 (27 May 2026) is the reporting message to C5, and only for a domestic invoice. MLS is the technical status: delivery between the Access Points, and C5's processing of the TDD. Invoice Response is a business status between trading partners and does not go to Finančná správa.
Endpoints, SBDH headers and error codes are on TDD and MLS.
ISDOC is a local format in Slovakia that aligns with EN 16931. The PSB converts ISDOC to BIS Billing 3.0.
eConnect has been PASR-certified since 28 May 2026. That is a national requirement on top of OpenPeppol certification. Invoices to a Slovak Peppol participant go out as BIS Billing 3.0. TDD reporting for a domestic flow belongs to that route, through the PSB. Rolling live domestic B2B traffic into production still needs internal steps at eConnect. If you only invoice from the Netherlands to Slovakia, it stays an ordinary Peppol invoice.
eConnect works with KROS for the local market. ISDOC conversion is part of that cooperation.
No. An invoice from the Netherlands to a Slovak company is an ordinary Peppol invoice in BIS Billing 3.0. No TDD goes to Finančná správa, and you do not need a PASR registration. The Slovak duty applies to domestic transactions. Only when you invoice from Slovakia to a Slovak buyer do you need a PASR-certified Access Point that sends BIS Billing 3.0 and files the TDD in parallel.
No. This is not clearance. The invoice travels from C1 through C2 and C3 to C4. C5 receives a TDD only on domestic traffic, alongside that route. A problem at C5 does not block the invoice.
MLS is the technical status. C3 sends MLS to C2 when the invoice is delivered, and C5 sends MLS back on the processing of the TDD. Invoice Response is a business status between supplier and buyer, for example whether the invoice is accepted commercially. That message does not go to Finančná správa.
Yes, if you work with ISDOC internally. The PSB converts ISDOC to BIS Billing 3.0 before the invoice goes onto Peppol. The buyer receives an EN 16931 document. The other way round, an incoming Peppol invoice can be converted to the format your system expects.