ISDOC

What it means

ISDOC is an open Czech XML format for electronic invoices. It was created in the Czech Republic as a shared standard of accounting software vendors and is now supported by many programs used in Slovakia too, especially those active in both markets.

An ISDOC file holds all the data of an invoice in a machine-readable structure: supplier, customer, line items, VAT rates, amounts and payment details. It is often sent together with a PDF or embedded in it, so a person sees a normal document while the software reads the data.

It is important to distinguish it from the European standard EN 16931 and the Peppol network. ISDOC is a national format with good practical support, but it is not the standard on which the mandatory electronic invoicing being prepared in Slovakia between VAT payers is built.

How it works in practice

The biggest benefit is on purchase invoices. If a supplier sends ISDOC, the accounting software loads it without retyping and without the errors that come from OCR extraction from a PDF. The accountant then checks only the posting and approval, not every amount.

When issuing invoices, check whether customers can receive ISDOC. Most programs with Czech roots can, but some customers will prefer a PDF, EDI or the format of their own network. For an easy transition, sending a PDF with an embedded ISDOC file works well.

An electronic invoice must contain the same invoice particulars as a paper one, and the recipient must agree to receive it. Authenticity of origin and integrity of content must also be ensured, for example through a reliable check of the invoice against the order and delivery.

What to watch out for

Once mandatory e-invoicing under EN 16931 arrives, ISDOC alone may not be enough. When choosing accounting software, ask whether it also supports the European format and a Peppol connection, so you do not have to switch systems in a few years or pay for an expensive converter.

The data in the XML and the image in the PDF must match. If the software produces different amounts, for example because of VAT rounding, it is unclear which figure applies. When going live, send test invoices and check how the recipient's system loads them.