Q&A about KSeF
Based on the SSoT (Source of Truth) - 630 verified facts. Internal KSeF probe: 147/150 PASS; vendor metric, not an official MF benchmark.
KSEF PRIVATE · ACTIVE PRODUCT
KSeF Private
local AI assistant
for accounting firms and businesses
Local BezChmury 11B model + 630 SSoT facts + FA(3) validator + error-code diagnosis. Designed to run locally after installation. Working data stays in the customer environment, with separately disclosed technical exceptions.
KSeF (Krajowy System e-Faktur, Poland's National e-Invoice System) is being rolled out in phases starting 1 February 2026 for VAT-registered businesses, with extensions to all taxpayers in 2026.
WHAT YOU GET
Six features, one source of truth.
Built-in SSoT knowledge base, schema validator and error-code diagnosis. Everything local.
API and ERP error diagnosis
Code 410 (session), 440 (duplicate referenceNumber), 450 (UPL-1 authorisation). Step-by-step fix instructions.
FA(3), QR, UPO and offline24 validator
Validates the FA(3) schema, QR code correctness, UPO and offline24 mode - all locally, with no data sent off your machine.
Current vs historical facts
Distinguishes the state effective from 1 February 2026 (40-day VAT refund) from the earlier state (60 days). Reduces unsupported-output risk through source-backed answers.
Sources and metadata-backed citations
Every answer includes a deterministic citation (article of the act, regulation, effective date).
Runs offline after install
Designed to run locally after installation. Technical exceptions such as activation, updates, support or KSeF connectivity are disclosed separately.
HOW IT WORKS
Three layers. Zero cloud.
Question classifier → topical collections (KSeF / VAT / JPK / ZUS) → BezChmury Engine (silnik 11B + RAG) → answer with deterministic citation.
1
Router (classifier)
Recognises the question type: error code, fact lookup, validation, smalltalk.
↓
2
SSoT collections
KSeF (218 records) · VAT (180) · JPK (87) · ZUS (95). Total of 630 facts.
↓
3
BezChmury 11B + RAG
Polish LLM, Q4_K_M quantisation (8 GB RAM). Local inference.
↓
→
Answer + citation
Every answer ships with a source citation (article, act, effective date).
WHO IT IS FOR
Three personas, one product.
Accounting firm
Marek K., 12-person team, 80 clients
Problem
Every client uses a different ERP and asks the same questions about KSeF. The support team was drowning in emails repeating the same explanations.
Benefit
40 hours per month saved on procedural questions. The team now focuses on declarations and tax optimisation rather than FAQ duty.
"The repetition is over. Our support team no longer answers the same question about code 440 eight times a day."
Sole-trader business (JDG)
E-commerce entrepreneur
Problem
KSeF went live, invoices full of schema errors, unsure whether to apply MPP, NIP in NrVatUE, or code 440.
Benefit
The FA(3) validator checks each invoice before submission. Code 440 diagnosis = referenceNumber duplicate, fix in 30 seconds.
"For the first time I understand what "NrVatUE only contains a foreign VAT number" actually means. Without consulting the MF glossary."
Finance manager at a mid-size company
CFO of a 50-200 person company
Problem
The ERP drifted out of sync with KSeF, errors are scaling up, IT does not know where code 410 (session) comes from, the auditor is waiting on the log.
Benefit
Group error diagnosis (codes 410/440/450) with a fix at the ERP level. Audit trail with a hash of every queried invoice.
"The auditor receives an export of every BezChmury query - every decision documented, no one can challenge it."
ERROR DIAGNOSIS
Codes 410, 440 and 450 - fix step by step.
The most common KSeF errors - diagnosed in 30 seconds. Full coverage: 30 numeric codes plus 10 logical patterns.
Code 410
Session expired / no authorisation
Refresh the session token. Verify TLS/HTTPS on the ERP side. Typical timeout is 60 minutes - our pipeline auto-renews the token.
Code 440
Duplicate invoice number (referenceNumber)
Check whether referenceNumber is unique across the whole year. The conflict usually comes from invoices imported before migration to KSeF.
Code 450
No permissions / UPL-1 expired
Renew UPL-1 in ePUAP. Check permissions in KSeF (Authorisations tab). The fix is often re-granting roles for the accountant.
KSEF PRIVATE FAQ
Frequently asked questions.
Does BezChmury KSeF Private really run offline?
The application is designed for local execution after installation: the SSoT knowledge base is bundled and the BezChmury 11B model runs on your computer (CPU or GPU). Internet may be needed for activation, updates, support or KSeF communication if the user enables it.
Does my data flow to the US, OpenAI or Anthropic?
The default mode is local/on-premise: user questions and documents are processed in the customer environment. Technical exceptions such as activation, updates, support or KSeF connectivity should be configured and disclosed separately.
How does the model know about KSeF and Polish regulations?
A bundled SSoT (Source of Truth) knowledge base contains 630 verified facts about KSeF, VAT and tax law. Every answer includes a source citation (article, regulation, date). We refresh the base every quarter via the Update Pack.
What happens after the annual Update Pack expires?
The application keeps running - only the knowledge base is frozen at the latest state. You can renew the Update Pack at any time without losing data.
Does BezChmury hallucinate? Can I trust the answers?
Our internal KSeF probe covered 150 control questions and scored 147/150 PASS; this is a vendor metric, not an official MF benchmark and not a guarantee for every matter. Every answer carries a source citation, so users should verify outputs against the cited sources.
Which error codes are supported?
All standard KSeF codes: 410 (session), 440 (duplicate referenceNumber), 450 (UPL-1 authorisation), plus 30 logical-pattern error codes mapped to step-by-step fixes.
What is the FA(3) validator?
It validates the invoice XML schema against the FA(3) specification published by the Ministry of Finance - before submission to KSeF. It catches schema errors, missing fields, malformed dates and incorrect GTU codes. FA(3) is the current invoice schema mandatory from 1 February 2026.
Does it support offline24 mode?
Yes. BezChmury recognises the offline24 procedure - when KSeF does not respond, how to issue invoices, how to upload them later and within what time limits.
How many users can share one licence?
KSeF Lite - 1 seat (PLN 1,490). KSeF Private - 3 seats (PLN 4,990). Accountant Private - 5 seats (PLN 9,990). Pro Bundle - 10 seats (PLN 14,900). Enterprise - unlimited (from PLN 49,900).
Does it run on macOS and Windows?
Yes. macOS (Apple Silicon and Intel) and Windows 10/11 (x64). The application is Electron-based + a local BezChmury 11B engine. Linux on-premise builds are available for Enterprise customers.
Want to see private AI
for your business?
A short KSeF Private demo (15 min). We will show local execution, control questions, source base and how BezChmury reduces the risk of hallucinations.