KSeF: how to prepare your company for structured invoices

The National e-Invoicing System turns an invoice from a document you send to your customer into a message exchanged through a central government platform. The change looks technical, but it touches very practical matters: who in your company is allowed to issue an invoice, when a document counts as issued, and where you get the data for booking your costs.

An invoice stops being a file you send

In the paper and PDF model, the invoice was created on your side and reached the recipient by post or e-mail. With KSeF you send the system a structured XML file that matches the current schema, the system assigns it a number and returns an official acknowledgement of receipt. Your customer downloads the document from the same place — you no longer have to send it, although you can still forward a PDF visualisation for convenience.

• Data enters the system in fixed fields, so there is no room for your own invoice layout or for notes outside the structure.
• Attachments and commercial arrangements stay outside the system — KSeF accepts the content of the invoice, not the correspondence.
• The recipient sees the document as soon as it is accepted, without waiting for an inbox.
• The number assigned by the system becomes the document's main identifier in dealings with the tax administration.

Permissions: who issues invoices in your company

Before the first invoice appears, somebody has to be entitled to act on the company's behalf. Owner-level rights belong to the taxpayer by default, and further rights are granted to the people and the software that actually work on documents.

1. Decide how you authenticate the company: a qualified signature, a qualified seal or the Trusted Profile of an authorised person.
2. Grant named permissions to the people who issue and receive documents — separately for issuing, separately for reading.
3. Generate a token for your accounting software if invoices are to be sent automatically, and protect it the way you protect banking access.
4. Agree the scope of access for your accounting office; read access to sales and cost invoices is usually enough.
5. Record who granted which permission and when — when staff change, this is the first thing that has to be revoked.

The KSeF number, the issue date and corrections

The most common misunderstanding concerns the date. A document counts as issued at the moment the system accepts it, not when you save it in your own software. If the submission gets stuck on validation, the invoice simply does not exist yet — and that shifts the whole chain: the payment term, the entry in the records and the moment revenue is recognised.

Fixing mistakes changes in the same way. There is no more “we will correct it and send it again”. You issue a correcting invoice that refers to the number of the original document, so the history of changes stays in the system permanently. In practice it is worth spending a minute checking your customer's details before sending rather than five minutes correcting afterwards.

What to do when there is no connection

The rules provide for situations in which sending is impossible: a failure on the system side, an announced maintenance window and a plain loss of internet access at the issuer. In each of these cases the invoice is created outside the system and is submitted later, within a deadline counted from the moment the obstacle ends. The visualisation of such a document carries a code that lets the recipient confirm it matches the original.

• Put the procedure in writing: who decides to switch to offline mode and who makes sure the documents are submitted afterwards.
• Check whether your software queues unsent invoices and retries by itself — manual lists in a spreadsheet always get lost.
• Rehearse the fallback scenario once, calmly, before it happens for real.

A plan for the coming weeks

1. Take stock: how many invoices you issue per month, from how many sources, and how many of them are created by hand.
2. Clean up your customer database — a tax number with a typo is a minor error today, but it blocks the document on submission.
3. Agree with your accounting office who downloads cost invoices and how often.
4. Send a dozen or so trial invoices in the test environment, including a correction and a prepayment invoice.
5. Train the people who issue documents — most of the trouble comes from habits, not from technology.

In Księgowskaz, sending and downloading invoices happens in the background: a document issued in the panel goes to the system, and cost invoices are pulled in automatically and wait to be posted. Preparation therefore comes down to putting your data and permissions in order, not to retyping documents.

A KSeF rollout is ninety per cent tidy data and ten per cent technology.