Polish VAT White List Verification n8n Workflow (NIP & Bank)

Verify Polish VAT status & bank assignment before you pay — automatically

This Polish VAT White List Verification n8n Workflow lets you submit a supplier’s NIP and bank account number, then checks them against Poland’s VAT White List API (wykazpodatnikowvat.mf.gov.pl) and logs the verification for audit purposes—ending with a clear pay / no-pay verdict.

What this workflow does

• Receives a submission from an n8n Form with: supplier NIP, bank account number, invoice number, and gross amount in PLN.
• Normalizes and validates inputs, including:
  • NIP checksum
  • Polish bank account number checksum (NRB / PL IBAN)
• If validation fails, it returns a completion message listing the detected errors.
• If validation succeeds, it calls the Poland VAT White List API to retrieve the supplier’s VAT status and verify whether the bank account is assigned to the NIP for today’s date.
• Builds a user-facing explanation with a verdict such as OK, NOT_ON_LIST, NOT_FOUND, CHECK, or ERROR, including the official requestId when available.
• Writes an audit record of each check (including requestId) to an n8n Data Table named vat_whitelist_checks.

Use cases

• AP teams validating Polish suppliers’ VAT White List status and bank assignment before releasing payments.
• Automation engineers deploying a ready-made n8n form-based compliance check with stored verification history.
• SaaS operators adding an NIP + bank verification step to workflows for purchase approvals.

Technical details

• Nodes / tools: if, set, code, form, data table, sticky note
• External API: wykazpodatnikowvat.mf.gov.pl (Poland Ministry of Finance VAT White List)
• Setup: run the manual trigger “create the checks table” once to create the vat_whitelist_checks Data Table
• Config options: API base URL, timezone, and a default large-payment threshold (15,000 PLN) can be adjusted