Structured Invoice – What It Is, How It Works, and How to Issue It via KSeF

Structured invoice - how it works, what it contains and how to issue it through KSeF

Do you issue VAT invoices? If so, you know that in 2026 everything will change. The traditional PDF invoice will be a thing of the past. It will be replaced by a structured invoice, that is, a document in XML format, sent directly to KSeF - the National e-Invoice System.

Sound like a technical revolution? Because it somewhat is. But rest assured - everything can be embraced. Below I explain how a structured invoice works, what it must contain and how to issue it in accordance with the regulations.

What is a structured invoice?

A structured invoice is simply an invoice in the form of an electronic XML file. Instead of a graphical document (like a PDF), we have a file that contains data written in a specific, standardized layout. This layout - or so-called schema - is determined by the Ministry of Finance and required by KSeF.

Importantly: the structured invoice does not go immediately to the contractor, as before. It must first be sent to KSeF. Only after receiving a reference number from the system is the invoice considered to have been issued.

What data does a structured invoice contain?

In terms of content, a structured invoice contains the same information as a classic VAT invoice. The difference is that the data must be entered in specific XML fields and according to a specific logic. There is no room for discretion.

What does a structured invoice in KSeF contain?

• Data of the seller and the buyer (TIN, name, address),

• invoice numbers and dates of issue,

• description of goods/services,

• VAT rates and amounts,

• payment terms,

• terms of delivery, if relevant,

• optional attachments or references to previous documents.

You can also add a "remarks" field, but even this must comply with the requirements of the structure.

How to issue a structured invoice?

Here there are two ways - depending on the scale and needs of the company.

1. through the MF application (demo or production).

This is a solution for micro-entrepreneurs or occasional issuers. The Ministry of Finance has provided a simple online form where you can manually fill in the data, sign and send the document to KSeF.

Pros:
- no cost,
- quick access,
- simple tool for beginners.

Minuses:
- not suitable for mass invoicing,
- no integration with ERP,
- everything has to be entered manually.

2. through a system integrated with KSeF.

For most companies - especially those that issue more than a few invoices per month - this is the only sensible option. Integration with KSeF can be either direct (if the company has its own IT) or indirect - through a platform like Infinite GIP.

How it works.

Your accounting system (ERP) generates invoice data, the intermediary system converts it to XML compatible with the KSeF schema, digitally signs it and sends it to the Ministry's system. After a while, you receive a return with confirmation that the invoice has been registered.

The whole thing can run in the background - automatically - without manual clicking.

What else is worth knowing?

• A structured invoice does not have a graphic form. If you want, you can generate a preview (e.g. for a customer), but formally only XML counts.

• KSeF does not send invoices to the contractor. You are the one who has to make it available to him - e.g. via email, platform, link to PDF.

• Once sent to KSeF, you cannot "undo" an invoice. You can correct it, but not delete it. It is worth testing the system well before implementation.

Summary

Structured invoice is not a fad, but a new obligation. As of July 2026, every VAT-covered company will have to issue it through KSeF. For some it's a big change, for others - a chance to simplify processes and eliminate errors.

The sooner you prepare, the less stress and cost on launch day. If you already have an ERP system - check if it is ready for integration. And if not - it's worth thinking about a platform that will do it for you.