Receiving invoices through KSeF has been mandatory for every Polish taxpayer since 1 February 2026, regardless of when a given company had to start issuing through it. The Ministry of Finance is explicit that the 1 April 2026 date deferred the issuing obligation only.
The catch is that KSeF is a pull system. No email lands in anyone's inbox, there is no unread folder, and a buyer cannot reject a document. The invoice simply sits in the system while its deduction window runs.
Here is where the gaps in a purchase register come from, where invoices hide, and what a monthly process needs to look like.
Nobody will tell you an invoice arrived
An invoice issued with your NIP (Polish tax identification number) in the Podmiot2 (buyer) field is available to you automatically, and since 1 February 2026 no buyer acceptance is required. "Available" only means you can retrieve it after authenticating: through the Ministry's free KSeF Taxpayer Application, its mobile app, or any software integrated with the KSeF 2.0 API.
If nobody queries the system, documents pile up quietly. A company with five suppliers notices a missing invoice. A company with fifty notices nothing until the VAT return looks thin.
The practical conclusion is that retrieval has to be scheduled, not left to whoever remembers to log in on Friday afternoon.
The receipt date decides your deduction period
This is where foreign-owned subsidiaries get caught most often. KSeF does not change VAT deduction deadlines, but it does change how the receipt date is established.
For invoices issued in online mode, offline24 mode, and the KSeF-unavailability mode, the receipt date is the day the KSeF number is assigned (Article 106na(3) of the Polish VAT Act). Article 106gb(4) lists the exceptions, including foreign buyers with no fixed establishment in Poland, consumers, and entities without a Polish tax number, where actual delivery of the document counts instead. Emergency mode is handled separately and generally falls back to actual receipt. The Ministry sets this out in its Q&A on issuing and receiving invoices.
A concrete example: your supplier submits the invoice on 30 June at 23:56 and the KSeF number is assigned on 1 July at 00:01. The receipt date is 1 July, so the earliest deduction period is July, even if your accountant pulls the file on 3 July. When you downloaded it is irrelevant.
Miss that period and the right survives: three following monthly periods, or two following quarterly ones, after which you are into amending a filed return. A missed cost rarely means lost VAT, but it always means rework and a mismatch between the ledger and the bank.
What is still not in KSeF (as of August 2026)
Assuming every cost lands in KSeF is wrong in 2026. Outside the system you will still find:
Micro suppliers under the threshold. Between 1 April and 31 December 2026, a taxpayer whose invoiced sales stay at or below PLN 10,000 gross per month may still issue on paper or as a PDF. That option closes on 1 January 2027. The Ministry explains the calculation on a dedicated page.
Cash registers and simplified receipts with a NIP up to PLN 450. Not required in KSeF until the end of 2026.
Foreign suppliers. A company with no registered seat or fixed establishment in Poland does not issue through KSeF. Those invoices arrive by email or through a supplier portal.
Employee purchases made in a private capacity. When the buyer field holds an individual rather than the company, the invoice is not subject to KSeF and comes back to you as paper or PDF.
Debit and credit notes. The Ministry confirms these are neither issued in nor transmitted to KSeF.
Documents issued during an announced KSeF outage. In that window every buyer, domestic taxpayers included, receives the invoice in an agreed form, paper included.
So "one place" cannot mean "the KSeF import only". It has to mean one register that absorbs both the KSeF feed and manually captured documents, tagged so they remain distinguishable in the JPK_V7 VAT reporting file.
Where invoices hide
A few recurring blind spots:
The Podmiot3 field. An invoice issued to your company but carrying a subsidiary unit, a branch (through the IDWew internal identifier), or an employee in role "11 – Employee" shows up in a different view than ordinary purchases. In the Ministry's Taxpayer Application it sits in a separate tab. If your software only pulls documents where you are the buyer, part of your cost base stays behind a wall.
Corrections with no original. Since the mandatory phase began, correction invoices go through KSeF even when the original was issued outside it. Your register receives a negative-amount document with nothing to net against.
Settlement invoices for advances. The FA(3) schema lists the referenced advance invoices but publishes no per-advance amount. Every tool has to make an assumption there, and a human has to check it.
Multiple tax numbers. An accounting firm, or an owner of three companies, authenticates to KSeF in the context of one taxpayer at a time. Without a multi-company panel that means repeating the whole retrieval ritual per entity.
How Biurko collects purchases
Concretely, without the marketing haze.
Scheduled pulls. You enable them per company and choose the direction: purchases, sales, or both. The default interval is six hours, and each run covers only the window not yet seen, with a one-hour safety overlap. There is also an on-demand pull for when you are waiting on a specific document. KSeF refuses metadata queries spanning more than three months, so longer ranges are split into chunks automatically.
Two phases: discovery, then confirmation. You first see the list of documents found, then decide whether to import everything or a selected subset. On a first run against six months of history that is the difference between control and a flood.
Duplicate handling. Three cases are detected: a document your own account issued coming back as a purchase, a repeated import of the same invoice, and a number collision with a manually entered invoice. Each ends in a skip with a stated reason rather than a second register entry.
A review flag instead of silent posting. Documents that need a bookkeeper's eye are marked: totals that do not add up (gross other than net plus VAT), a correction whose original could not be located, a line with neither a net nor a gross amount, a settlement invoice referencing several advances, and, with schema validation enabled, an XSD mismatch. You clear the flag once you have reconciled the document.
An exportable purchase register. CSV or XLSX with issue date, receipt date, KSeF number, invoice number, supplier NIP and name, net and VAT split by rate, gross total, cost category, JPK marker, and document source. Filters by period, counterparty, cost category, and JPK marker.
Non-KSeF documents. A paper invoice, a PDF from a foreign supplier, or a receipt goes in manually, with a suggested JPK marker: OFF for a document issued while KSeF was down, BFK for a document legitimately outside KSeF, DI for a receipt treated as an invoice. You can attach the scan or PDF to the entry.
What we do not do. We do not guess the cost category: it is a company-specific taxonomy where a wrong guess costs more than a click. We do not yet read data out of PDFs, that is on the roadmap and not in the product. And the KSeF import does not overwrite the receipt-date field, so if you rely on it for reporting, fill it in deliberately.
The monthly routine: seven steps, no gaps
Turn on scheduled purchase pulls and set the interval to six hours or less.
Clear the review-flagged documents weekly instead of letting them stack up to period close.
Check Podmiot3 documents separately if you have branches, subsidiary units, or employee purchases.
Keep a list of suppliers still invoicing outside KSeF and watch that channel deliberately.
Enter non-KSeF documents with the correct JPK marker before you close the period.
Reconcile the purchase register against the bank statement: a payment with no invoice is the clearest signal of a missing cost.
Export the purchase register for the period and hand it over together with the list of open items.
Wrapping up
A complete purchase register in 2026 is not one feature, it is a rhythm: regular pulls from KSeF, a deliberate reading of the receipt date, and a separate lane for documents that will never appear in the system. It is worth having that rhythm rehearsed before 1 January 2027, when KSeF numbers enter bank transfer titles and penalties begin.
Biurko gives you scheduled purchase pulls, duplicate detection, review flags, and purchase register exports in one panel, across several companies if you run more than one. Create a free account and connect KSeF in a few minutes.
Related reading: [SLUG-KSEF-CORRECTIONS], [SLUG-OFFLINE24-MODE], [SLUG-KSEF-FOREIGN-SUBSIDIARY].
FAQ
Does KSeF notify you when a purchase invoice arrives? No. An invoice issued to your tax number is available automatically, but you only reach it by authenticating and retrieving the invoice list, either in the Ministry's free tools or in software integrated with the KSeF 2.0 API. Scheduling that retrieval is the practical answer.
What counts as the receipt date for an invoice pulled from KSeF? As a rule, the day the KSeF number was assigned, not the day you downloaded the document. Exceptions cover the cases listed in Article 106gb(4) of the VAT Act, such as foreign buyers and consumers, and emergency mode, where actual receipt applies.
Can a buyer reject an invoice in KSeF? The rules provide no rejection mechanism. If an invoice is wrong, the seller issues a correction invoice through KSeF, even when the original was issued outside it. Commercial disputes are settled outside the system.
What about suppliers who do not issue through KSeF yet? Until 31 December 2026 the smallest taxpayers may invoice outside the system while their invoiced monthly sales stay at or below PLN 10,000 gross. You accept such an invoice normally and keep the deduction right, but you have to enter it into your register by hand.
How often should invoices be pulled from KSeF? For most companies a few times a day is enough, and Biurko defaults to every six hours. With many suppliers and monthly VAT settlement, a shorter interval keeps the review queue small before period close.