KSeF was designed to run around the clock. In reality, any IT system goes down sometimes — and your office internet has a habit of failing exactly when a client is waiting for an invoice. Polish law planned for this: in those situations you issue the invoice in one of several special modes, and the printout shows two QR codes marked "OFFLINE."
The catch is that few people know what those codes actually do or why there are two of them. And this is not a cosmetic detail — from 1 January 2027, uploading an invoice to KSeF late can cost up to 100% of the VAT.
This article explains what each QR code is for, where the offline code comes from, how the offline24, offline, and emergency modes differ, and the deadline for getting the document into KSeF.
Why an offline invoice carries two QR codes
When an invoice is created outside KSeF, the system cannot confirm two things in real time: that the document exists and that you are the one who issued it. So the rules require two independent QR codes, each doing a different job.
This is not double protection "just in case." Each code has a distinct function, and without either one the offline invoice is incomplete.
Code I — the identification QR ("OFFLINE")
The first code is for identification. Your invoicing software generates it automatically, and it holds the document's core data: invoice number, seller NIP (Polish tax ID), amounts, and dates. A verification link is woven into the code as well.
This lets the buyer scan the code with a phone and check the invoice before it even reaches KSeF. The code carries a visible "OFFLINE" marker — a signal that the document was issued in a special mode and is still waiting to be uploaded.
This code asks nothing of you beyond a correctly generated FA(3) structure — the mandatory invoice schema since 1 February 2026.
Code II — the QR from the KSeF type 2 certificate
The second code handles authentication, and it causes the most trouble. It is built from a KSeF type 2 certificate (also called the offline certificate or the issuer's certificate). Its job is to prove that the invoice was issued by an authorized party — with no connection to the system, relying on a trusted certificate instead.
Here is the crux: without a type 2 certificate you cannot issue an invoice in offline mode at all. No certificate means no second QR code, which means no valid invoice during an outage.
You obtain the certificate in the Certificate and Permissions Module (MCU) of the KSeF 2.0 Taxpayer Application. It became available on 1 November 2025 and usable from the start of mandatory KSeF. The certificate is valid for two years, so it is worth noting its expiry date in advance.
The three offline modes and upload deadlines
"Offline mode" is really several separate procedures. They differ by cause and — most importantly — by the deadline for uploading the invoice to KSeF.
Mode When to use it Deadline to upload to KSeF offline24 Voluntary, any time — e.g. no internet, KSeF running slow, your own choice By the next business day after the issue date offline (unavailability) The Ministry of Finance announces a planned maintenance break in the BIP (official public bulletin) By the next business day after the break ends emergency (awaria) The Ministry announces a KSeF outage in the BIP or via API Within 7 business days of the outage ending total outage Extraordinary situation (e.g. natural disaster) No obligation to upload; paper/PDF without FA(3) or QR is allowed
Two points worth remembering. First, the issue date stays whatever you put on the document — even if you upload it later. Second, in emergency mode the 7-day clock runs from the end of the outage, and if the Ministry announces another outage during that window, the count restarts from the end of the second one.
Example: you issue an invoice on 8 July 2026 in offline24 mode because the office internet went down. The issue date is 8 July. You must upload the invoice to KSeF by 9 July at the latest (the next business day). If you don't, the issue date stays the same — but from 2027 you expose yourself to a penalty.
The current rules for all special modes are published at ksef.podatki.gov.pl.
Where Biurko fits in
At Biurko we built offline handling so you're not left with manual work at the worst possible moment:
Certificate first. We chose certificate-based authentication over tokens — the same type 2 certificate you need for the second QR code. That way you don't have to scramble to obtain it on the day of the outage.
Offline code and QR on the PDF automatically. An invoice issued in a special mode gets its offline reference code and a QR with a verification link straight onto the printout — no manual assembly.
Auto-resubmit after an outage. Once KSeF comes back, queued offline invoices are sent automatically, without you lifting a finger.
Deadline watch. If an invoice nears its "next business day" or "7-day" limit, the system flags it for review and notifies the responsible person — before the deadline lapses.
Practical checklist for a KSeF outage
Obtain your KSeF type 2 certificate in the MCU before you need it — without it you cannot issue an offline invoice.
Note the certificate's expiry date in your calendar (valid two years).
Confirm your software generates both QR codes and the FA(3) structure.
Memorize the deadlines: offline24 and unavailability — next business day; emergency — 7 business days from the end of the outage.
Watch Ministry of Finance announcements in the BIP — that's where unavailability and outages are declared.
After KSeF recovers, verify that every offline invoice was actually accepted and assigned a KSeF number.
Conclusion
The two QR codes on an offline invoice aren't decoration — they're two independent proofs: that the invoice exists, and that an authorized party issued it. The key to the second one is the type 2 certificate; without it, the whole offline mode stops working. And since you must upload the invoice to KSeF within a strict deadline anyway, it pays to have a tool that does it for you.
Biurko generates offline codes and QR codes automatically, resubmits after an outage, and tracks deadlines on your behalf. Try it free for 14 days at biurko.io — no card, no commitment.
FAQ
Why are there two QR codes on an offline invoice? The first code identifies the invoice and lets the buyer verify it before it's uploaded to KSeF. The second, generated from a KSeF type 2 certificate, confirms the issuer's identity. Both are required for an invoice issued in offline mode to be complete and compliant.
Do I need a KSeF certificate for offline mode? Yes. The KSeF type 2 certificate (offline certificate) is required to generate the second, authenticating QR code in every special mode: offline24, offline, and emergency. Without it you cannot issue an invoice outside the system. You obtain it in the MCU of the KSeF 2.0 Taxpayer Application.
How long do I have to upload an offline invoice to KSeF? In offline24 mode — by the next business day after the issue date. In unavailability mode — the next business day after the break ends. In emergency mode — within 7 business days of the end of an outage announced by the Ministry of Finance.
What happens if I miss the upload deadline? The invoice's issue date won't change, but from 1 January 2027 a missed deadline can trigger a penalty under Article 106ni of the VAT Act — up to 100% of the VAT amount (invoice with VAT) or up to 18.7% of the total due (invoice without VAT).
How will I know KSeF is down? The Ministry of Finance announces unavailability and outages in the Public Information Bulletin (BIP) and via the API. That announcement determines whether you use unavailability mode (next business day) or emergency mode (7 business days).