Updated 25 September 2026. Poland now clears almost every domestic B2B invoice through KSeF, the Ministry of Finance's central platform, and a paper or PDF invoice between two Polish VAT payers is no longer valid. What KSeF does not touch is the inbound foreign invoice, the receipt and the older document. For a Polish biuro rachunkowe, that residual flow is still large.
Is e-invoicing mandatory in Poland in 2026?
Yes. Since 1 February 2026 the largest taxpayers, and since 1 April 2026 all other VAT-registered businesses, must issue domestic B2B invoices through KSeF in the FA(3) XML schema. The Ministry of Finance reported that more than 35 million invoices passed through KSeF between 1 and 26 February 2026 alone.
When did the B2B mandate start, and who is still outside it?
Large taxpayers with 2024 sales above PLN 200 million started on 1 February 2026; everyone else on 1 April 2026. Micro-entrepreneurs with monthly sales up to PLN 10,000 gross have until 1 January 2027, and no financial penalties apply during 2026. From 1 January 2027 enforcement begins in full for all groups.
Which format and platform does Poland use?
The FA(3) structured XML schema, submitted to and validated by KSeF; an invoice is legally issued only once KSeF has accepted it and assigned its number. There is no Peppol layer. During the voluntary phase from 2022 only a small fraction of invoices used the system; more than 152,000 entities issued through it in February 2026.
Does KSeF cover foreign supplier invoices?
No. A supplier without a Polish VAT registration cannot access KSeF, so invoices from foreign vendors keep arriving as PDF or paper and are reported through the monthly VAT return with the relevant document codes. The same applies to B2C receipts and simplified invoices under PLN 450. Those documents are exactly what Invoreg reads at line level.
Which VAT rates apply in Poland and how does Invoreg map them?
23 % standard, 8 % and 5 % reduced, plus 0 % and exempt supplies. Invoreg reads each line, whether a KSeF document or a German supplier's PDF, and maps the rate to the corresponding tax code in your accounting software. Poland's VAT compliance gap was 16.0 % in 2023, among the higher figures in the EU, which is why KSeF went ahead in 2026 after an earlier postponement.
What should an accounting firm in Poland do now?
Separate the two flows. KSeF-issued sales and purchase invoices come from the platform in structured form; everything else, including foreign invoices, receipts and pre-April 2026 paper, needs capture. Use email intake so client mailboxes forward that residual flow, and turn on duplicate detection before the penalty regime starts on 1 January 2027.
What Invoreg handles in Poland today
- Polish NIP numbers (10 digits, shown as PL + NIP on intra-EU invoices) on vendor records
- 23 %, 8 %, 5 %, 0 % and exempt lines mapped to the tax codes in your accounting software
- Polish-language invoices and receipts, including paragon z NIP simplified invoices
- Foreign supplier invoices in English, German and other languages that fall outside KSeF
- Multi-organisation workspaces for a biuro rachunkowe serving dozens of clients
Related
Sources
- Poland announces new timeline for mandatory e-invoicing — EY, accessed September 2026
- Poland e-invoicing, e-reporting and KSeF mandate: briefing document — VATupdate, 2 May 2026
- Over 35 million invoices issued in KSeF since mandatory e-invoicing began in February 2026 — VATupdate, 4 March 2026
- The EU's Questionable VAT Policy — Tax Foundation, 2 February 2026