How to switch invoicing software in Poland safely?

Maybe you inherited an iFirma account from a Polish bookkeeper, or inFakt from whoever set up the local branch. Now you want to switch invoicing software in Poland, and the one thing stopping you is the data: hundreds of customers and a few years of invoices, with help pages that exist only in Polish.

The timing matters. KSeF (Poland's national e-invoicing system) has been mandatory for most businesses since 1 April 2026. The smallest ones, with monthly invoiced sales up to PLN 10,000 gross, were exempt only until the end of 2026.

This guide covers what you can export from iFirma, inFakt and wFirma, what KSeF can give back, and the order to do it in. I build invoicing software, I am not an accountant, so agree the switch date with yours.

Your invoice history may already be in a government system

Start here, because it changes the whole plan. Receiving invoices through KSeF has been mandatory for everyone since 1 February 2026, and issuing them since 1 April 2026 for most firms (Ministry of Finance). So an invoice you issued from iFirma, inFakt or wFirma after that date sits in KSeF, whichever program sent it.

KSeF keeps structured invoices for 10 years from the end of the year of issue (Article 112aa of the VAT Act, as quoted from Ministry answers by Infor). After that you are responsible for your own archive.

What KSeF will not give you:

• invoices from before your firm was obliged to use it, unless you sent them voluntarily,

• proforma invoices and drafts,

• payments recorded after issue (an invoice in KSeF never changes),

• the look of your PDFs: logo and layout.

Take a typical case (an illustration, not a client story): a Polish limited company (sp. z o.o.) owned from abroad, on iFirma since January 2024. Everything issued from April 2026 comes back in one KSeF download. The earlier invoices stay as PDFs. You will not need them to issue new invoices, but the tax office and your accountant may ask for them, and invoices outside KSeF must be kept until the tax liability expires, generally five years from the end of the year in which the tax was due.

Contacts: getting them out of iFirma, inFakt and wFirma

Menu names below are the Polish ones you will see on screen, with a gloss.

iFirma

Contractors live in the CRM module on the CRM dashboard (Pulpit CRM), with separate import and export functions. The catch, per iFirma's help: contractor export only works in the Księgowość internetowa (online accounting) and Biuro rachunkowe (accounting office) packages. Import is available in every package, including the free invoicing one.

If iFirma is your destination, mind the limit: one import is a CSV file with at most 500 contractors, so split larger lists. The button "Pobierz format pliku" (download file format) gives you a template.

inFakt

inFakt has a public API (REST and JSON), so contacts can be pulled without a manual export, and competitors use it. wFirma imports contractors from inFakt with just an API key. Fakturownia imports clients, products and invoices under Ustawienia > Import (Settings > Import). You generate the API key on the inFakt side.

One tip from Fakturownia's help: fill in your company data first, or the import fails with a seller-name error.

wFirma

wFirma takes contractors from a CSV file: CRM » KONTRAHENCI » Importuj z pliku (CRM » Contractors » Import from file). The import window shows the required column order, and you choose the character encoding and field separator. If Polish letters turn into garbage, encoding is usually the cause.

For export, wFirma's help describes sales invoices only (VAT, non-VAT, margin, corrections, advances), in formats made for Insert, Streamsoft Ala and Comarch Optima, under Ustawienia » Inne » Import i eksport danych (Settings » Other » Import and export of data). Receipts (rachunki) are excluded. I did not find an export of the contractor list itself in the help, so if you do not see one in the CRM, ask wFirma support for a file.

What Biurko does today

I will only describe what works now.

Biurko pulls your history from KSeF once the company is connected to it. You choose a date range and a direction (sales, purchases or both), and the import covers the whole range, without picking invoices one by one. If an import is already running it resumes instead of duplicating. A new contractor is added by typing the NIP (Polish tax ID), and the details fill in from the GUS company registry. You set the starting number of an invoice series, so your first Biurko invoice follows the last one from the old program. The interface is available in English as well as Polish and Ukrainian.

Why year-end, and why no panic

From 1 January 2027 the KSeF obligation also reaches the smallest firms. Penalties were set by law to start the same day, but the government adopted a bill on 20 October moving them to 1 January 2028, and the Sejm passed it in early November. It now goes to the Senate (status on 10 November 2026). The obligation itself does not move. Switch for clean numbering and VAT records, not because something hits you on 1 January.

Checklist: seven steps

1. Keep the old account active until the last month is settled.

2. Pick a cut-off date at the start of a settlement month, and agree it with your accountant so the VAT records for one month are produced in one program.

3. Export your contacts (CSV, or the inFakt API) and open the file in a spreadsheet. Check tax IDs, duplicates and Polish characters.

4. Import 10 test rows first, then the full list.

5. Download your KSeF history: purchases from 1 February 2026, sales from 1 April 2026 (earlier if you sent invoices voluntarily).

6. Set the starting number of each series to follow your last invoice.

7. Save a PDF archive of pre-KSeF invoices, and only then cancel the old subscription.

Summary

Contacts move by CSV or API. Your invoice history is most reliably recovered from KSeF, not from an export file. PDF design, later payments and pre-KSeF invoices will not travel, so archive them.

Want to see how much history comes back without retyping? Create a Biurko account at biurko.io, connect your company to KSeF and pull your own invoices. The first 14 days are free.

FAQ

Can I export invoices from iFirma to another program?

I did not find an export of invoice history for another program in iFirma's public help. Invoices issued since 2026 are in KSeF, and you can download them from there. Keep older ones as a PDF archive. Ask iFirma support if unsure, because features depend on your package.

How do I move contacts from inFakt to wFirma?

Use the API route. In wFirma open Ustawienia » Inne » Import i eksport danych, choose inFakt and enter the API key generated in inFakt. You can also tick the option to correct imported data against the GUS registry. This moves contractor data only. Invoice history needs another source, such as KSeF.

Are KSeF invoices enough to migrate my invoice history?

For invoices issued and received through KSeF, yes. They will not cover invoices from before you were obliged to use KSeF unless sent voluntarily, proformas, drafts or payments recorded after issue. Keep those in a PDF archive from the old program before you close the account.

How many contacts can I import into iFirma at once?

According to iFirma's help, one import handles a CSV file of up to 500 contractors, so split a bigger list into several files. Import works in every package, while contractor export is only available in the online accounting and accounting office packages.

When is the best time to switch invoicing software in Poland?

Usually at the start of a settlement month, so the VAT records for a month come from one program. Agree the date with your accountant. You are not forced to switch before 1 January 2027, because penalties for KSeF errors are expected to be postponed to 2028.