Duplicity

What should I do if e-invoice is submitted twice?

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

Short answer

First determine whether both submissions contain identical XML. The same hash indicates repeated delivery of the same document; a different hash means the content differs and requires deeper investigation. Notify the customer and record in the audit trail how each attempt was handled and which document is valid.

Hash

Same or different

The hash will quickly show if it is the same XML content.

Customer

Notify about duplication

Especially if you don't know how his system handles replays.

Validity

Determine the correct attempt

The audit must show which version is relevant.

Prevention

Retro blocking

The system is supposed to prevent uncontrolled double sending.

Detailed explanation

Sending a duplicate invoice need not be a tax disaster, provided it is transparently documented and the recipient does not process the document twice. The problem arises when there are two different versions of the same invoice or when an automatic import is carried out without a duplicate check.

As set out in the Act

Accounting and tax processing must be verifiable. If two transmissions of the same document occur, the company must be able to explain what happened and prevent duplicate processing.

Practical examples

  • The same invoice was sent twice due to a retry; the customer marks it as a duplicate.
  • The second XML file has a different due date, so the supplier must explain the correction.
  • The ERP system blocks the third attempt until the user confirms the reason.

Most common mistakes

  • “I’ll quietly ignore the second attempt.” It needs to be flagged in the audit.
  • “The same invoice number is sufficient.” Compare the hash and the content as well.
  • “The customer will sort it out somehow.” The supplier should communicate the risk of duplication.

Conclusion

Resolve duplicate submission by comparing hashes, preserving the audit trail and communicating the confirmed outcome to the customer.

Legal basis

  • Act No. 431/2002 Coll. on accounting
  • Act No. 222/2004 Coll. on VAT
  • Internal duplicate rules

Related questions

This is not legal advice. Sources: Act No. 222/2004 Coll. on VAT, Slovak Financial Administration e-invoicing FAQ, OpenPeppol BIS Billing 3.0 and the Slovak e-Invoicing Centre’s internal validation model. Verified on 7 July 2026.