KSeF Number in Bank Transfers from 2027: What Changes and Why April 2026 Is a Myth
Art. 108g makes the KSeF number mandatory in bank transfer titles from 1 January 2027, including split payments. Two wrong dates are circulating online. Here is what the law actually says, who is affected, and how to prepare.
KSeF Number in Bank Transfers from 2027: What Changes and Why April 2026 Is a Myth
From 1 January 2027, every bank transfer between active VAT payers in Poland must carry the KSeF number of the invoice being paid. The rule is in art. 108g of the VAT Act. The Ministry of Finance confirmed the date on 29 May 2026 on the official KSeF portal: the obligation to provide the KSeF number in payment titles is deferred until the end of 2026.
Two wrong dates are circulating in online content. One says April 2026. The other says August 2026. Both are false. They trace to an unconfirmed rumour about JPK_V7 reporting and to pre-launch draft documents that were superseded. If you have seen either date, disregard it. The verified date is 1 January 2027.
What Art. 108g Actually Says
The obligation applies to transfers between active VAT payers for invoices issued through KSeF. The KSeF number is a 35-character identifier assigned by the system when an invoice is accepted. It must appear in the transfer title.
Scope and exclusions:
| Payment method | In scope? | Notes |
|---|---|---|
| Standard bank transfer (elixir) | Yes | KSeF number in title |
| Express transfer (BlueCash, Express Elixir) | Yes | KSeF number in title |
| Split payment (MPP) | Yes | KSeF number plus the collective identifier for batch payments |
| BLIK | No | Not a bank transfer |
| Card payment | No | Not a bank transfer |
| Cash | No | Not a bank transfer |
The split payment (MPP) case deserves attention. The KSeF number must appear in the communication field of the MPP transfer, alongside the existing requirements for split-payment messages. For batch payments covering multiple invoices, a collective identifier allows one transfer to reference several KSeF numbers, so you do not need to send a separate transfer for each invoice.
Who Is Affected
Every business that pays supplier invoices by bank transfer and is an active VAT payer. If you pay by BLIK, card, or cash, the obligation does not apply to those payments. If your supplier is not a VAT payer (or is exempt), the obligation does not apply to payments to them.
The practical impact falls heaviest on accounting offices running batch payments. A biuro paying 40 supplier invoices in two monthly batch runs needs to restructure its bank templates to include KSeF numbers in transfer titles. The collective identifier helps, but the workflow change is real: someone needs to look up the KSeF number for each invoice and insert it into the payment template.
Why the KSeF Number in Transfers Matters Beyond Compliance
The payment-title rule is not just a compliance burden. It creates the infrastructure for deterministic payment matching.
Today, matching payments to invoices is manual. An accountant looks at a bank statement, reads the transfer title, guesses which invoice it corresponds to, and posts the payment. Transfer titles are inconsistent. Buyers truncate invoice numbers, use their own reference numbers, or write nothing useful. The matching error rate is high enough that reconciliation is a dedicated monthly task in every accounting office.
From 1 January 2027, the KSeF number in the transfer title makes matching deterministic. The 35-character identifier is unique per invoice. A matching engine can extract it from the bank feed, look it up in KSeF, and post the payment automatically. Split-payment-aware matching handles the MPP case. The reconciliation task shrinks from hours of manual work to an automated process that runs in seconds.
This is why building the matching engine in H2 2026 is a first-mover advantage. The day the mandate switches on, every accounting office in Poland needs it. The product that ships it first captures the demand.
Debunking the Wrong Dates
The "April 2026" myth
This date traces to pre-launch draft documents and vendor blog posts that conflated the KSeF number in payment titles with the Phase II mandate date (1 April 2026). The Phase II date is real: it is when all remaining VAT payers were obliged to issue through KSeF. The payment-title date is 1 January 2027. They are different obligations in different articles of the VAT Act.
The "August 2026" myth
This date traces to an unconfirmed rumour that JPK_V7 reporting would require the KSeF number starting August 2026. The Ministry of Finance has not confirmed this. As of 28 July 2026, no regulation or komunikat requires the KSeF number in JPK_V7 before 2027. Treat any August 2026 date as unconfirmed and do not reconfigure your processes based on it.
How to verify dates yourself
The authoritative source is ksef.podatki.gov.pl. The page titled "Podstawy prawne oraz kluczowe terminy" was last updated 29 May 2026 and states the 1 January 2027 date explicitly. If a blog post or vendor article cites a different date, check whether it links to the official portal or to another blog post. Content farms cite each other in circular chains. The official portal cites the statute.
Preparation Checklist for December 2026
Run through this list before the obligation takes effect.
- Banking templates: Update transfer templates in your banking interface to include a field for the KSeF number. Most Polish banks will release template updates in Q4 2026.
- Accounting software: Confirm your accounting tool can store the KSeF number per invoice and insert it into the payment file (export to the bank).
- Batch payment workflows: If your biuro runs batch payments, plan how the collective identifier will be used. Map which invoices go into which batch.
- Standing orders and recurring payments: Review existing standing orders that pay supplier invoices. They will need the KSeF number added.
- Contractor communication: Inform your buyers that from January 2027, your transfer titles will carry the KSeF number. Some buyers' systems may need to parse it.
- Staff training: Brief anyone who initiates transfers on the new requirement. The penalty for non-compliance starts on 1 January 2027.
- Reconciliation process: If you match payments manually, plan the transition to KSeF-number-based matching. If your software supports it, configure the matching rules before January.
What Happens on 1 January 2027
Four obligations converge on that date. The KSeF number in payment titles is one. The other three: penalties for invoices issued outside KSeF activate (up to 100% of VAT under art. 106ni), the 10,000 PLN monthly paper concession ends permanently, and the Ministry's workflow improvement package changes token and status mechanics.
If you prepare for the payment-title obligation in isolation, you miss the compound effect. A business that has not transitioned its banking templates, has not trained its staff, and discovers in January that its transfer titles are non-compliant faces the penalty regime at the same time. The preparation window is Q4 2026. Do not wait until January.
This material is information of a general nature and does not constitute legal or tax advice. For a specific situation, verify the current rules or consult a qualified adviser.