Poland's Finance Ministry released KSeF version 5.5.1.v1, refining its API, removing error codes, and adding new authorisation options.
Poland updates e-invoice-KSeF technical specification
Public
Poland
Author: Nikolina Basić
Category:
Technical description
Views:
41
Content accuracy validation date:
15.07.2026
Content accuracy validation time:
00:00h
The Polish Ministry of Finance has released version 5.5.1.v1 of the KSeF e-invoicing technical specification, refining the API interface ahead of the mandatory rollout.
The changes refer to:
- Error code removal: Error code 99 for HTTP 400 (Bad Request) responses has been withdrawn, aligning error handling with how the API actually works.
- New authorisation option: Taxpayers can now use “kwota przychodu” (revenue amount) as an authorisation parameter in selected schemas. This is especially useful for individuals and micro-entities that don’t rely on qualified signatures or ZAW-FA authorisations.
The update is technical only — it does not introduce new invoicing obligations for taxpayers. However, software providers, ERP vendors, and API integrators must adapt their systems to ensure smooth operation with the revised specification.
Other news from Poland
Adjustment of regulations on cash registers in Poland
Public
Poland
Author: Nikolina Basić
Poland
Author: Nikolina Basić
Starting January 1, 2027, invoices will be issued exclusively via KSeF, with consultations held for proposed changes and token management. Starting January 1, 2027, invoices will no longer be issued through cash registers. Instead, they must be issued exclusively via the KSeF system- e-invoicing system. To prepare for this change, the Ministry of Finance and Economy of Poland has published a draf... Read more
New webinar was uploaded: Recorded webinar: Evolution of Fiscalization:From fiscal printers to real-time data platforms
Author: Dušan Bučevac
Fiscalization has transformed from a compliance tool reliant on hardware to dynamic, software-driven platforms linking businesses and tax authorities. The webinar was presented by Dušan Bučevac, Sales Manager at Fiscal Solutions, who covered crucial fiscalization milestones and explained how real-time data has reshaped compliance, transparency, and business decision-making. Read more
Subscribe to get access to the latest news, documents, webinars and educations.
Already subscriber? Login
Poland: KSeF Invoice Visualization vs. Transaction Confirmation
Poland
Author: Ema Stamenković
Under KSeF, a structured invoice legally exists only once it receives a KSeF number; until then, the buyer may receive only a transaction confirmation, which is not an invoice and does not allow VAT deduction. Read more
Subscribe to get access to the latest news, documents, webinars and educations.
Already subscriber? Login
Poland Plans New Tourist Tax Legislation
Public
Poland
Author: Ema Stamenković
Poland
Author: Ema Stamenković
A new Polish bill would allow municipalities to introduce a daily tourist compensation fee for overnight stays, with limited exemptions. A new bill amending the Act on Local Taxes and Fees has been submitted to the Polish Sejm, allowing Municipal Councils to introduce a so-called "tourist compensation fee" collected at hotels. According to the bill's proponents, this is not a new tax but a fee. If... Read more
Poland: Consultation on VAT Refunds for Foreign Taxpayers
Public
Poland
Author: Ema Stamenković
Poland
Author: Ema Stamenković
Poland is consulting on VAT refund rule changes for foreign taxpayers to align refund claims with KSeF e-invoicing requirements from 2026. The draft relaxes invoice attachment obligations but requires KSeF invoice identification numbers where available, with different evidence rules for EU and non-EU claimants. Poland has launched a public consultation (opened April 15, 2026, by the Ministry of Fi... Read more
Poland: KSef Errors and Possible Penalties
Poland
Author: Ema Stamenković
Poland’s KSeF rules provide a grace period in 2026, meaning taxpayers will not face financial sanctions for KSeF-related mistakes while adapting to the system. Let's delve deeper into this! Read more
Subscribe to get access to the latest news, documents, webinars and educations.
Already subscriber? Login