How to Validate Invoices Before Sending to KSeF

The KSeF system rejects invoices with structural errors (XSD) and selected substantive violations. A rejection means the invoice was not accepted and no KSeF number is assigned — you need to fix it and resubmit. The KSeF receipt date of the resubmission may differ from the intended issue date, which can shift the VAT settlement period.

Pre-validation eliminates this problem: you check the invoice before sending it. Errors are visible immediately, and corrections can be made before transmission. This is especially important for batch submissions, where a single invalid file can block the entire package.

1. 1
   Download and install KSeF Guard

   MSI installer (~30 MB) or portable ZIP (no admin required). Available at ksefguard.pl/en/download.

2. 2
   Drag XML files onto the application window

   You can drag a single file or an entire folder. The application automatically detects XML files and starts scanning.

3. 3
   Review results

   Each error includes: rule ID, problem description (PL + EN), fix suggestions, legal source citation, and XML source preview with the highlighted element.

4. 4
   Export the report

   Available formats: TXT, CSV, JSON, PDF. The PDF report includes the full legal chain — you can attach it to audit documentation.

The KSeF Guard CLI is designed for automation and CI/CD pipeline integration. Available on Windows and Linux.

ksef-guard validate invoice.xml

ksef-guard validate --format json --output results.json ./invoices/

ksef-guard validate --format pdf --output report.pdf ./invoices/

ksef-guard validate --preset maximum ./invoices/

The CLI returns exit codes that can be used in scripts and CI/CD pipelines:

Full exit code reference available on the documentation page.

• Missing P_14_*W fields (BUS-003) — foreign currency invoice without VAT amounts converted to PLN
• Arithmetic mismatches (BUS-044) — line net value does not match quantity × adjusted unit price
• Missing exchange rate (BUS-006) — foreign currency invoice without a conversion rate
• Future date (BUS-030) — issue date more than 30 days in the future
• Missing exempt-rate summary bucket (BUS-088) — “zw” (exempt) rate without P_13_7 summary bucket

KSeF Guard checks 128 active validation rules derived from the VAT Act and the Ministry of Finance brochure. Rules include source-backed evidence appropriate to each rule class — you can verify exactly why a given error is detected.

KSeF Guard can be integrated with any CI/CD system. Here is a GitHub Actions workflow template that downloads the CLI and validates your invoices:

- name: Download ksef-guard
  run: |
    curl -fsSL -o ksef-guard.tar.gz \
      "https://www.ksefguard.pl/downloads/ksef-guard-linux-amd64.tar.gz"
    tar -xzf ksef-guard.tar.gz && chmod +x ksef-guard

- name: Validate invoices
  run: ./ksef-guard validate --format json --output results.json ./invoices/

More detailed examples (GitLab CI, YAML configuration) are available on the documentation page.