Which identifiers should be stored for an e-invoice?
Short answer
§ 74 of the VAT Act and EN16931/Peppol BIS Billing 3.0 require the invoice number and identification of the parties, including the company registration number, VAT identification number or tax identification number, as applicable, and the Peppol EndpointID. An internal invoice ID, XML hash, submission ID, status or event ID and idempotency key are recommended technical records for integration and audit purposes; they are not additional statutory invoice particulars.
Invoice details
Serial number, dates, identification of parties, including ID number/VAT number/VAT number.
Mandatory BT fields and EndpointID
Invoice number and page identifiers in XML structure, EndpointID for routing.
Internal invoiceId, XML hash
Useful for integration and auditing, not a legal requirement.
submissionId, statusId/eventId
They help pair the webhook with the document and deal with support with the provider.
Conclusion
§ 74 and the applicable e-invoicing rules distinguish required invoice and party identifiers, including the EndpointID, from additional technical identifiers retained as good integration and audit practice.
Sources
- Law no. 222/2004 Z. z. Coll. on VAT, § 74 (invoice requirements)
- Law no. 222/2004 Z. z. Coll. on VAT, § 76a (as amended by Act No. 385/2025 Z. z. Coll.) — general obligations of the delivery service provider, reference to the technical standard
- EN 16931 and Peppol BIS Billing 3.0 — mandatory document and party identifiers, EndpointID
the VAT Act · current FAQ of the Financial Administration of the Slovak Republic on e-invoice · Peppol BIS Billing 3.0
Not legal advice.