Frequently asked questions about KSeF and KSeFGPT

Describe what you need in your own words, for example: “Show invoices from January” or “Find invoices from this supplier”. Once your account is connected to KSeF, the assistant helps you find and analyze your invoices and prepare data for a new invoice. It also answers questions about KSeF using knowledge that we keep up to date. Explore AI Chat.

KSeFGPT is first and foremost a tool built to use artificial intelligence to support entrepreneurs in their everyday work with invoices and KSeF. It helps issue, send, receive and organize FA(3) documents, while AI makes it easier to analyze incoming and outgoing invoices and prepare data before handing it to accounting.

Yes. The KSeFGPT chat lets you issue an invoice to a contractor without manually clicking through a form. You can simply describe in natural language who the invoice is for, which line items to add, which dates to use and which payment terms should apply. The AI Assistant prepares the invoice data, fills the FA(3) structure, shows an XML preview and lets you quickly move on to review before sending the invoice to KSeF.

KSeFGPT offers paid plans and a 7-day PRO trial that starts after registration. After the trial, the account becomes inactive if payment is not made or is cancelled. However, several tools are completely free and require no registration.

Without an account you can use, among others, the KSeF XML validator, PDF-to-XML and XML-to-PDF converters, the XML invoice generator and the correction tool. You will find them under /darmowe-narzedzia.

Yes. In the app you can issue a structured FA(3) invoice, send it to KSeF, check its status and download the UPO, as well as receive incoming invoices issued by your contractors.

Yes. KSeFGPT supports import and bulk sending of invoices, including from Excel files, which speeds up work with larger volumes of documents.

The fastest way is to use one precise prompt in chat. For example: "Issue an invoice for <contractor name>. Invoice number: <invoice number>, add <number of line items> items. Here are the items: <list the items here, including quantity and all other required details>, place of issue: <city>, issue date: <issue date>, service date: <service date>, payment due date: <payment due date>, payment method: <payment method>. Use the bank account assigned to this account. Show the XML preview. In the footer add the following information: <information>." The more precise your input is, the faster the Assistant will prepare a ready invoice draft for review and sending.

KSeF, Poland’s National e-Invoice System, is a Ministry of Finance system for issuing, receiving and storing structured invoices in XML format. It currently uses the FA(3) structure. Once a document is accepted, the system assigns a unique KSeF number, separate from the invoice number assigned by the issuer.

In stages: from 1 February 2026 for the largest taxpayers (sales above PLN 200 million) and from 1 April 2026 for the rest. Mandatory receiving of invoices applies to everyone from 1 February 2026, and the smallest taxpayers join from 1 January 2027.

It is an invoice in a uniform XML format compliant with the FA(3) logical structure, sent to KSeF. Once accepted, the system assigns it a KSeF number and stores it in a uniform form for every issuer.

The issuer assigns the invoice's own number in field P_2, while the KSeF number is assigned by the system only after the document is accepted and returned, among others, in the UPO. It is worth keeping both identifiers.

No. KSeF handles individual invoices, while JPK_VAT reports the VAT records and settlement for a period. From the February 2026 settlement, the JPK_V7M(3) and JPK_V7K(3) versions apply, with the NrKSeF field and the OFF, BFK and DI markers.

No. Mandatory KSeF covers B2B transactions. Consumer invoices remain outside the obligation, although they can be issued in KSeF voluntarily.

It is a monthly gross threshold counted only for invoices subject to mandatory KSeF. Once exceeded, the invoice that crosses it and all subsequent ones must go to KSeF, with no return to the preference in later months. The preference applies until 31 December 2026.

The law provides emergency modes. In offline24 and during unavailability you send the invoice no later than the next business day; during an announced outage you have 7 business days; during a total outage the invoice is not sent to the system.

A correction to a structured invoice is, as a rule, also issued as a structured invoice carrying the KSeF number of the corrected invoice. The VAT period for the correction depends on its type and cause, not only on the number's date.