Required XML archive and recommended proofs

How must e-invoices be archived, and what must be retained?

Short answer

Under § 85o ods. 15, a VAT payer retains e-invoice for ten years after the end of the calendar year to which it relates. From the statutory definition of e-invoice, the Financial Administration derives an obligation to retain the XML. A PDF need not be stored together with the XML, but throughout the retention period the invoice must be capable of being displayed in a human-readable form within a reasonable time on request. Attachments, confirmations and audit records form an important evidence package, although not all of them are expressly included in the duty under § 85o ods. 15.

Mandatory

XML and ten years

The payer archives the e-invoice in XML for ten years from the end of the relevant calendar year.

Readability

Viewer is enough

The PDF does not need to be saved; However, the XML must be able to be displayed or printed in a reasonable amount of time.

Recommended

Attachments and statuses

Delivery confirmations, attachments and links to corrections strengthen evidence, but they must be distinguished from the core of Section 85o(15).

Provider

The contract is not your law

Long-term access to the postman depends on the contract; the payer must ensure the fulfillment of his own obligation.

Statutory minimum

Section 85o(15) stipulates a ten-year retention period for electronic invoices from the end of the calendar year to which they relate. In Example No. 59, the Financial Administration explicitly concludes that the taxpayer is obliged to archive electronic invoices in XML format.

PDF and readability

PDF is not a mandatory archive format. According to the technical section of the FAQs, it is sufficient for a taxable person to be able, upon request and within a reasonable time, to generate a readable output from the XML file, either on screen or in print. The XML file must therefore not be discarded once a PDF has been created.

What else is sensible to keep

For the purposes of an audit, dispute or migration, it is advisable to retain, alongside the XML file, any attachments, the Message ID, confirmation of dispatch and delivery, error statuses and links to corrective documents. This constitutes a recommended evidence package; we do not claim that each of these elements is specifically named in Section 85o(15).

Change of provider

The law imposes an archiving obligation on the taxpayer. Therefore, do not assume, without checking the contract, that the provider will maintain online access for the entire statutory period. Before changing your solution, request an export of the XML and related evidence.

Conclusion

The mandatory core is a ten-year XML archive and preserved readability. PDF is an optional preview; attachments and status evidence are a recommended part of a secure archive.

Legal and technical basis

Section 85o(4) and (15) of the VAT Act
Section 71(3) of the VAT Act
Financial Administration FAQ, Example No. 59 and Technical Examples Nos. 7, 14 and 15

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. 59: Archiving of e-invoices: Is there an obligation to archive e-invoices in their original XML format, or is another form of archiving also permissible (i.e. is conversion to another format permissible)? Does the procedure differ between the supplier and the recipient of the e-invoice? Does the procedure differ depending on whether the party is a VAT payer or merely a taxable person under the VAT Act?

From 1 January 2027, the procedure set out in Section 85o(15) of the VAT Act, as in force until 30 June 2030, will apply, under which the payer is obliged to retain an electronic invoice for a period of ten years from the end of the calendar year to which the electronic invoice relates. An electronic invoice is any document or notification which contains the particulars specified in Section 74(1) and is drawn up, sent and received in an electronic document format that allows for its automated and electronic processing, and in a data structure compliant with the technical standard for electronic invoicing and the list of its syntaxes as set out in a separate regulation. On the basis of the above, the taxpayer is obliged to archive electronic invoices in XML format.

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: The payer is obliged to archive an electronic invoice for a period of ten years from the end of the calendar year to which it relates. In the event of a tax audit, what invoices will I need to submit?

Current conclusion: The taxpayer must retain the e-invoice for ten years from the end of the year to which it relates, and, according to the current FAQ, must archive it in XML. PDF or printed copies are for readability purposes only, not as a substitute for the original XML.

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.