Poland FAQ

Frequently asked questions about invoicing compliance in Poland

Compliance questions

When does mandatory KSeF invoicing start in Poland?

1 February 2026 for taxpayers with turnover above PLN 200M and 1 April 2026 for everyone else (large/medium businesses) — schedule confirmed by Sejm in mid-2024 after delays. B2C is optional. Foreign-only businesses without a fixed Polish establishment are out of scope.

Who can act as a supplier in Poland?

Any entity with a Polish NIP and active KSeF access. Large taxpayers (turnover > PLN 200M) must be onboarded by 1 February 2026; the rest by 1 April 2026. Foreign-only entities without a Polish fixed establishment cannot use KSeF.

What are the legal obligations for receiving invoices in Poland?

Once KSeF is mandatory, all B2B invoices must be received through KSeF — paper or PDF rejection is no longer permitted between Polish parties. Archival is automatic in KSeF for 10 years; recipients can pull copies at any time.

What periodic reporting obligations exist in Poland?

JPK_V7M (monthly) or JPK_V7K (quarterly) consolidated VAT and SAF-T file. Once KSeF is mandatory, JPK_V7 is expected to draw directly from KSeF data, eliminating manual reconciliation.

What types of invoices are supported in Invopop's KSeF integration?

Currently supported invoice types:

• Standard Invoices (FAT): Regular B2B invoices with FA(3) schema
• Credit Notes (KOR): Invoice corrections and adjustments

All invoices must include the pl-favat-v3 addon in GOBL to ensure FA(3) schema compliance.

Additional invoice types can be supported based on customer requirements. Contact support if you need specific invoice types.

Will B2C transactions need to be reported in KSeF?

No. B2C invoices in KSeF are optional. The mandatory requirement applies only to B2B transactions.

Are there special supplier obligations under KSeF?

The KSeF certificate must belong to the company account directly or to a user with both InvoiceRead and InvoiceWrite permissions in KSeF. Suppliers must declare KSeF as their issuer in the Ministry of Finance taxpayer’s portal before going live.

What are the legal obligations for receiving invoices through KSeF?

Once KSeF is mandatory, all Polish B2B recipients must accept KSeF-issued invoices. KSeF itself archives for 10 years; recipients have no separate archival duty for the structured XML.

Invoicing questions

What happens when I send an invoice to a foreign recipient?

International (cross-border) invoices are handled just like domestic invoices in KSeF:

• The invoice is created in GOBL with the foreign recipient’s details
• It’s converted to FA(3) XML format and submitted to KSeF
• KSeF validates and clears the invoice, assigning a unique KSeF ID
• The invoice is registered in the KSeF system

However, since foreign recipients cannot access KSeF, you must deliver the invoice through other channels (email, EDI, etc.). Include the KSeF QR code in the delivery for verification purposes.

What's the difference between test, demo, and production environments?

Test mode (sandbox only): Uses self-signed certificates generated automatically by Invopop. Perfect for quick testing without accessing the KSeF portal. Invoices are not sent to real KSeF servers.

Demo mode (sandbox only): Connects to the official KSeF Demo Portal. Requires manual certificate generation, simulating the full production flow in a safe test environment.

Production mode (live workspace): Connects to the live KSeF Portal. Requires valid company credentials and certificates. All invoices are submitted to the official KSeF system.

Use test mode for initial integration testing, then switch to demo mode when you’re ready to simulate the real certificate flow before going live.

What KSeF applications and portals are available?

Official KSeF applications:

• KSeF Taxpayer Application – the main portal with all functionalities
• KSeF Mobile Application – a mobile app for on-the-go access
• e-mikrofirma – a simplified portal aimed at micro-entrepreneurs

For testing:

• KSeF Demo Portal – demo environment for testing

How do I configure my workspace for Polish invoicing?

Install the KSeF Poland app, register your supplier (Test, Demo, or Production environment), and run invoices through the Send Invoice workflow. Each environment requires its own NIP and certificate setup.

I get a "failed to create session (Status 403 Forbidden)" error when sending an invoice to KSeF. What does it mean?

This error means the uploaded KSeF certificate does not have the required permissions to issue invoices. This typically happens when the certificate was uploaded by someone who is not the company administrator and only has limited permissions granted by the main company account.

The KSeF certificate uploaded to Invopop must belong to either:

• The company account directly logged into KSeF, or
• An entity that has both InvoiceRead and InvoiceWrite permissions (managed within KSeF)

To resolve this, you have two options:

1. Grant permissions in KSeF: The company admin (or whoever has direct access to the KSeF company account) grants InvoiceRead and InvoiceWrite permissions to the user who uploaded the certificate to Invopop. This can be done from the KSeF application portal and requires no further action in Invopop (no need to unregister/register).
2. Re-register with a new certificate: Unregister the supplier in Invopop and register it again using a certificate generated from the main KSeF company account (or another account with the required permissions).

Where do I find Poland-specific GOBL documentation?

See the Poland tax regime in GOBL for tax categories and NIP rules. The pl-favat-v3 addon documents the FA(3) schema fields required for KSeF.

Registering supplier questions

Why did my supplier registration fail?

Common reasons for registration failures:

• Certificate and private key mismatch: Ensure you uploaded both files from the same certificate generation
• Incorrect password: Verify the password matches what you set during certificate generation
• Future start date: Certificate start date must be today or in the past
• Wrong portal environment: Demo certificates won’t work with production, and vice versa
• File encoding issues: For API uploads, ensure files are properly base64-encoded
• Expired certificate: Check that the certificate is still valid
• Invalid NIP: Verify the Polish Tax ID is correct and has access to KSeF

Check the workflow error logs in the Invopop Console for detailed error messages that can help diagnose the specific issue.

I don't have a Polish NIP for testing. How can I get one?

For sandbox testing:

• Test mode: Generate fake NIPs at http://generatory.it/. These work immediately with self-signed certificates.
• Demo mode: You need a real NIP with access to the KSeF Demo Portal.

How do I onboard a new supplier in Poland?

Choose an environment (Test, Demo, or Production). Generate a KSeF certificate from the relevant portal (or use a self-signed cert in Test mode), upload it to Invopop with the matching password, and register the supplier through the KSeF Register Supplier workflow.

What certificates does KSeF require to authenticate a supplier?

A KSeF certificate exported as PKCS#12 (.p12) with password, generated through the KSeF Application Portal (or auto-generated by Invopop in Test mode). The certificate must have InvoiceRead + InvoiceWrite permissions.

How are supplier credentials stored in Invopop for Poland?

The KSeF certificate (PKCS#12 .p12 with password) is stored encrypted at rest. Invopop uses it to authenticate session creation with KSeF on the supplier’s behalf; the password is never returned in API responses.

Receiving questions

How do I import received invoices from suppliers?

Invopop automatically imports received invoices through a polling service:

1. Configure polling interval during party registration (hourly, daily, weekly, or monthly)
2. Set up the sync workflow to query KSeF for new invoices
3. Configure the import workflow to convert FA(3) XML to GOBL format
4. Link the workflows in the Poland app configuration

The system automatically checks KSeF at your chosen interval and imports any new invoices to your configured folder.

For manual import, use the API to trigger import jobs with specific KSeF numbers or date ranges. See the Import Received Invoices section in the guide.

Can I import historical invoices or backfill missed invoices?

Yes. You can manually trigger a sync workflow to import invoices from a specific date range using the Create a Job endpoint.

Pass the from and upto date parameters to sync all invoices received within that period:

{
  "workflow_id": "YOUR_SYNC_WORKFLOW_ID",
  "entry_id": "YOUR_PARTY_ENTRY_ID",
  "args": {
    "from": "2026-01-01T00:00:00Z",
    "upto": "2026-01-31T23:59:59Z"
  }
}

This is useful for backfilling invoices after a polling outage or importing historical data before enabling automatic polling.

How do I know if my automatic invoice import is working?

Check these indicators:

1. Polling configuration: Verify the polling interval is set in your party registration workflow configuration
2. App configuration: Confirm the Poland app has your sync workflow configured
3. Recent imports: Check the “Invoices · Expenses” folder for newly imported invoices
4. Job logs: Review job logs in the Console for sync and import workflow executions
5. Error notifications: Set up email or Slack notifications in your workflow error handling to alert you of failures

Test the import by manually triggering the sync workflow with a date range that includes known received invoices.

What format do received KSeF invoices arrive in?

FA(3) XML conforming to the Ministry of Finance schema. Each invoice carries a unique KSeF reference (numer KSeF) plus the issuer’s signature and a QR code linking to the public verification page.

How does Invopop convert received Polish invoices into GOBL?

Inbound FA(3) XMLs are parsed via gobl.favat. Tax rates, line items, and parties map onto GOBL fields; the original signed XML is preserved as a silo entry attachment.

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