Check your implementation for accuracy and avoid tax risks
Is your KSeF implementation functioning correctly and compliant with current VAT regulations?
In practice, many companies continue to make errors after implementing KSeF, which may lead to incorrect reporting, operational issues, and tax exposure.
We conduct a KSeF audit, identify issues, and help you resolve them.
What is a KSeF audit and when should it be carried out?
A KSeF audit is a comprehensive assessment of the implementation of the Polish National e-Invoicing System (KSeF), covering both tax and system perspectives.
Its purpose is to verify whether:
- invoices are correctly generated and transmitted to KSeF
- data complies with the logical structure of the e-Invoice
- accounting and sales processes are aligned with VAT regulations
When is a KSeF audit particularly recommended?
- after completing KSeF implementation
- when invoice errors or rejections occur
- during the implementation phase
- when changes are made to ERP systems or accounting processes
From a tax advisor’s perspective, an audit helps reduce the risk of errors that may result in financial and operational consequences.
Most common KSeF implementation errors and post-implementation issues
In practice, KSeF audits most frequently identify recurring problems:
- incorrect data affecting VAT settlements
- non-compliance with applicable regulations
- lack of control over e-Invoice accuracy
Technical and integration issues:
- incorrect integration between KSeF and ERP systems
- errors in invoice data mapping
- non-compliance with the current FA(3) structure
- issues with handling KSeF statuses
Process-related issues:
- lack of procedures for handling corrections within KSeF
- incorrect issuance of advance invoices
- lack of consistency between systems
Tax risks:
- incorrect data affecting VAT settlements
- non-compliance with applicable regulations
- lack of control over e-Invoice accuracy
The result?
Problems with settlements, risk of penalties, and disruption to business processes.
KSeF audit – what it includes and how we assess implementation quality
We conduct KSeF audits based on experience from implementation projects and tax advisory practice.
Scope of the KSeF audit:
- verification of KSeF integration
- API communication review
- validation of transmitted data
- VAT compliance assessment
- invoice data accuracy review
- identification of tax risks
- sales invoices
- corrective invoices
- advance payments and settlements
- document workflow analysis
- system consistency checks
- contingency procedures
Post-implementation KSeF support - ongoing assistance and optimisation
Following the audit, we also provide post-implementation KSeF support, which includes:
- tax and system consultations
- assistance with day-to-day issues and errors
- adaptation to regulatory changes
- support for accounting and IT teams
This ensures that KSeF implementation is not a one-off project, but a stable and secure ongoing process.
How a KSeF audit works step by step
identification of issues and scope
access to data and configuration
verification of real-life scenarios
concrete actions to implement
Who is the KSeF audit for?
This service is particularly recommended for:
- manufacturing companies
- e-commerce businesses
- service providers
- corporate groups
- organisations with complex ERP systems
KSeF audit delivered by tax advisors and KSeF experts
The audit is carried out by a team combining expertise in:
- tax advisory (VAT, e-Invoicing)
- KSeF system integration
This ensures we assess both legal and technical aspects.
Contact us:

Janina Fornalik
Partner | Tax AdviserE: janina.fornalik@mddp.plT: (+48) 660 440 141

Krzysztof Jaros
Manager | Attorney-at-law E: krzysztof.jaros@mddp.pl T: (+48) 504 399 980
KSeF Audit – frequently asked questions
How can I check whether KSeF is working correctly?
The most effective method is a KSeF audit covering system, data, and process analysis.
How long does a KSeF audit take?
Typically up to 4 weeks.
Is a KSeF audit mandatory?
No, but it significantly reduces the risk of errors and tax penalties.
Do you provide support after implementation?
Yes – we offer comprehensive post-implementation KSeF support.
What are the most common KSeF errors?
They mainly relate to integration, data mapping, and VAT compliance.
