What is BT-10 (customer reference) and when is it mandatory in e-invoice?
Short answer
BT-10 is a field for the customer reference — an internal code, contact person name or other identifier that the customer has communicated to the supplier for the purpose of processing the invoice in their system. It is not the customer's ID number or VAT number. Peppol BIS Billing 3.0 requires the invoice to contain at least one of two fields: either BT-10 (customer reference) or BT-13 (order number).
Customer reference
Internal code or reference, not IČO or VAT number.
Order number
Alternative to BT-10 if there is a formal order.
At least one of the two
The invoice must contain BT-10 or BT-13, otherwise it will not pass validation.
From the customer
The supplier does not invent the reference, he receives it from the customer in advance.
Conclusion
BT-10 is the customer's reference needed for its internal processing of the invoice; according to the BR-CO-10 rule, it must be filled in whenever the invoice does not contain the order number BT-13.
Sources
- Peppol BIS Billing 3.0 / EN 16931, business rule BR-CO-10
- Law no. 222/2004 Z. z. Coll. on VAT, § 74 (invoice requirements, customer reference is not a mandatory tax requirement)
Not legal advice. Machine-translated answer, not yet manually reviewed. For the exact wording, see the Slovak original.