Testing 2026

Are e-invoices sent during 2026 testing reported to the Financial Administration?

⚠ Machine-translated answer, not yet manually reviewed. For the exact wording, see the Slovak original.

Short answer

A test environment must be distinguished from voluntary production exchange. Pure test documents are not reported to the Financial Administration. For voluntary production exchange, the Financial Administration FAQ described a plan under which, once C2 and C5 were ready, C2 would report invoices of issuers identified by a VAT identification number; launch was planned for the third quarter of 2026. The actual technical availability and the applicable statutory scope must therefore be checked for a production exchange.

Test

No sharp accounting

It serves to verify techniques and processes.

Voluntary exchange

Real document

If it's production, it has to sit with accounting.

C2

Partner

Delivery between mailmen and recipient.

C5

Financial Administration

Separate data flow according to Slovak rules.

Detailed explanation

Testing is intended to verify XML, validation, the mail server, participant lookup, delivery and error statuses; a test document must not be mistakenly posted as a live invoice. A voluntary production e-invoice is a different case: it is a genuine document sent to a partner and, following the technical launch of C5, may be reported if the issuer has a VAT registration number on the document. It is therefore not sufficient to designate the whole of 2026 as a non-reporting period.

As set out in the law and technical rules

This distinction is clear from the latest materials from the Financial Administration: the presentation FAQ states that test documents are not reported, whilst the technical FAQ on voluntary production exchange sets out a plan for reporting from C2 to C5 once the interfaces are ready, but only for invoices issued by issuers with a VAT registration number. The mandatory regime from 2027 is governed by Sections 76a and 85o of the VAT Act.

Practical examples

  • A company in the testbed sends a test XML file with a fictitious number. This is not a live invoice.
  • In 2026, two partners will voluntarily exchange a production e-invoice and archive it as an accounting document.
  • The system will test C2 delivery, but C5 reporting is disabled or in a separate test mode.

Common misconceptions

  • “Nothing is ever reported in 2026.” Too broad. The testbed is not reported, but for voluntary production exchanges, the FS planned C5 reporting from Q3/2026 following the technical launch.
  • “C2 and C5 are the same flow.” No. C2 delivers to the partner; C5 is FS reporting.
  • “Every test XML is reported.” No. Purely test documents are not reported to the Financial Administration.

Conclusion

Pure test documents are not reported; voluntary production exchange is assessed separately and may use C2-to-C5 reporting after the relevant technical service is launched.

Legal and technical basis

  • Slovak Financial Administration, FAQ 9/VAT/2025/IM, example no. 44
  • Slovak Financial Administration, e-Invoice presentation FAQ, page 40
  • Act No. 222/2004 Coll. on VAT, Section 76a a Section 85o

Related questions

This does not constitute legal advice. Primary sources: FAQ Financial Administration of the Slovak Republic k e-invoice; Act No. 222/2004 Coll. on VAT as effective from 1. 1. 2027. Further sources: Act No. 222/2004 Coll. on VAT, Act No. 385/2025 Coll., Act No. 431/2002 Coll. on Accounting, official methodological and information materials from the Slovak Financial Administration on eInvoicing, EN 16931, Peppol BIS Billing 3.0 and OpenPeppol eDelivery documentation. Verified on 13 July 2026.

Official cases from the Slovak Financial Administration’s FAQs

The following questions and answers are taken from the current July FAQ from the Financial Administration and have been assigned to this topic. Grouping the cases prevents the creation of duplicate pages, whilst retaining the full answer and the exact wording of the question.

Example No. 44: Voluntary participation in Peppol in 2026: If we voluntarily join the Peppol network in 2026 and send an e-invoice via C2, whilst we are not obliged to report data: will C2 automatically report the data to C5 as early as 2026? Will the same arrangement apply in 2027? Will it be possible to withdraw from voluntary participation before 2027, or during 2027?

Yes, it will report the data, provided that C2 and C5 are ready for this; we expect reporting to commence in Q3/2026. It is the case that C2 reports to C5 only those invoices where the issuer has a VAT registration number. The regime will remain the same in 2027. It is necessary to comply with the law, under which a taxable person is obliged to receive/send an e-invoice.

Primary source: Financial Administration of the Slovak Republic, FAQ 9/VAT/2025/IM k e-invoice, July 2026 update. Processed and checked on 13 July 2026.

Review of questions from an earlier presentation

The presentation by the Slovak Accountants’ Centre was used solely to identify practical issues. The following conclusion has been updated in line with a subsequent FAQ from the Financial Administration and the applicable legislation; we do not treat the author’s suggestions, recommendations or incorrectly merged fragments as legal rules.

  • slide/page 40: If I join the trial operation of a certified delivery-service provider, will the data from the invoices issued be reported to the Financial Administration?

Current conclusion: Documents issued purely for testing purposes are not reported to the Financial Administration. Voluntary production-level exchange operates under a different regime; a more recent FAQ envisaged C5 reporting following the technical launch for invoices issued by a supplier with a VAT registration number. An older presentation cannot therefore be the sole source of information.

Primary sources: FAQ Financial Administration of the Slovak Republic k e-invoice, July 2026; Act No. 222/2004 Coll. on VAT Effective from 1. 1. 2027. Revised 13 July 2026.