KSeF Offline Modes: offline24, Outages and Emergency Mode

KSeF has four ways to issue an invoice when you cannot send it straight away, and each has its own deadline for sending it to the system afterwards. Offline24 is your own choice and gives you until the next working day. An announced unavailability (planned work) gives you until the next working day after it ends. An announced failure (the emergency mode, tryb awaryjny) gives you seven working days after it ends. A total failure announced in the media removes the duty to send at all. An invoice shown to a buyer outside KSeF carries two QR codes, KOD I and KOD II.

This page is for the accounts-payable or finance lead who needs a plan for the day KSeF, Poland's national e-invoicing system, is down or the company's own connection fails. It sets out the four situations, the deadlines, who receives the invoice and how, and the two QR codes. Shop checkout is not covered. GoRoute is a certified Peppol Access Point and SMP (POP000991). Its KSeF pack sends invoices to KSeF production, keeps the KSeF number and the UPO receipt (KSeF's signed proof of acceptance), and prints KOD I on the invoice PDF.

What are the KSeF offline modes?

There are three modes in which you issue an FA(3) invoice and send it later, plus one in which you do not send it at all. The Ministry's technical documentation sets them out in a table.

In the first three the invoice is issued electronically in the FA(3) structure, and the date of issue is the date in the invoice's P_1 field.

What are the deadlines when a failure is announced during the wait?

The clock moves. The technical documentation says that in offline24 and unavailability modes, if a KSeF failure is announced while the invoice is waiting to be sent, the deadline is counted from the day the last announced failure ends, and no longer than seven working days.

In emergency mode, a second failure announced during the seven days restarts the count from the end of that second failure.

Announcing a total failure during any of these ends the duty to send the invoices to KSeF.

Sending late is not a harmless slip. The Ministry's FAQ lists "did not send to KSeF in time an invoice issued in offline24 mode or during a failure or unavailability" among the breaches fined from 1 January 2027. KSeF in 2027 gives the size of the fine.

What happens in a total failure?

You go back to the pre-KSeF rules. The Ministry's answers say that during a total failure, announced in the media, taxpayers issue invoices as they did before mandatory KSeF: on paper or in any electronic form, with no duty to use the FA(3) structure and no duty to send them to KSeF after the failure ends. Such invoices carry no QR codes, and are handed to the buyer by any channel.

A correction issued while KSeF works is issued in KSeF as normal, even if the original was issued during the total failure. A correction issued during a failure is issued outside KSeF in the same way.

Who receives an offline invoice, and how?

A domestic buyer with a NIP receives it through KSeF in offline24 and unavailability modes. The Ministry's answer on offline24 is direct: because KSeF delivers the invoice to the buyer, a Polish taxpayer with a NIP should not be handed an invoice outside the system. The exceptions in article 106gb(4) of the VAT Act cover buyers who cannot get a document from KSeF:

• a buyer with no seat or fixed place of business in Poland;
• a buyer with a seat abroad whose Polish fixed establishment is not involved in the purchase;
• a buyer who uses the small-business VAT exemption of article 113a(1);
• a buyer with no tax identifier;
• a private person who is not in business;
• a purchase whose place of supply is outside Poland.

For these, the seller gives the invoice in a way agreed with the buyer, such as a PDF or print-out. During an announced KSeF failure (emergency mode), all buyers, domestic ones included, receive the invoice in the agreed form, even on paper.

If an invoice has no KSeF number yet, the seller may give the buyer a transaction confirmation (potwierdzenie transakcji) with two QR codes. The Ministry says it is not an invoice, and VAT cannot be deducted on it. It also says free Ministry tools cannot produce one, and commercial software may offer it. KSeF for foreign companies covers the buyers outside Poland in more detail.

What are KOD I and KOD II?

Two QR codes with two jobs. An online invoice shown outside KSeF carries one, KOD I. An offline invoice carries both.

• KOD I checks the invoice. It is a link built from the seller's NIP, the issue date and the SHA-256 hash of the invoice file. Scanning it shows a short summary and whether the invoice is in KSeF. Under the code is the KSeF number once there is one, or the word OFFLINE until then.
• KOD II checks the issuer. It exists only for invoices issued in an offline mode. It is a link signed with the private key of a KSeF certificate of the Offline type, which proves that the issuer is allowed to issue in the seller's name. Under the code is the word CERTYFIKAT.

A type 1 (Authentication) certificate cannot make KOD II. The Ministry's FAQ says the Offline certificate, type 2, is what an offline invoice handed over outside KSeF needs. KSeF certificates and tokens explains how to get one.

The codes must follow ISO/IEC 18004:2024 and are made by the issuer's software from the invoice data. Where the invoice cannot hold a code, it is supplied as a separate image or link.

What can the free Ministry tools do?

Online only. The Ministry says the free Taxpayer Application and the mobile application do not offer an offline mode. A business that wants offline24, or a prepared emergency routine, needs commercial software that supports it. That is worth asking about before the deadline, not on the day of an outage.

GoRoute's KSeF reference says that when an invoice is accepted, the PDF gets the KSeF number and KOD I. It does not describe issuing in an offline mode, so do not assume the pack does that. Ask us what it does in your case.

What should you do before 1 January?

1. Decide who watches for announcements. Unavailability and failure notices appear in the Ministry's BIP and in interface software. Total failure is announced in the media.
2. Decide who may use offline24, and who checks the next-working-day deadline.
3. Get an Offline certificate if you will hand offline invoices to buyers outside KSeF.
4. Make a list of buyers outside KSeF's reach (foreign, consumer, no NIP) and agree how each receives an invoice.
5. Tell your accountant that an offline24 or unavailability invoice handed over outside KSeF, with no KSeF number when the VAT file is sent, is marked DI in the JPK_VAT file and corrected to the KSeF number once it arrives. That is the Ministry's FAQ rule.
6. Run a drill. Issue one invoice in the test environment and walk through the send-later step.

What to do next

To see how GoRoute sends invoices to KSeF and prints KOD I, read the Poland e-invoicing page and the KSeF setup reference. Then book a demo to talk through your own outage plan, or see the tutorials.

Related reading

• KSeF in 2027: what changes on 1 January, including the fine for late sending.
• KSeF certificates and tokens, the Offline certificate.
• KSeF for foreign companies, buyers outside Poland.
• Poland KSeF 2026: migration path for Peppol-first architectures, the clearance model.
• KSeF for online stores, the shop tutorial.

Sources, all read on 5 November 2026: Ministry of Finance technical documentation, Tryby offline (table of issuing modes) and Kody QR; Ministry of Finance, KSeF website, Tryb offline i kody QR (27 April 2026); Wystawianie i otrzymywanie faktur; Zasady obowiązywania KSeF i przepisy prawne; Najczęstsze pytania; Pytania i odpowiedzi KSeF 2.0; GoRoute, Poland — KSeF setup and receipts. This is not tax or legal advice.