KSeF · API · Invoice automation
KSeF integration
Invoices from Poland’s National e-Invoicing System (KSeF) can land in your spreadsheet, CRM or accounting system on their own, with no logging in or downloading files. I build integrations with the KSeF API for companies and accounting offices.
In short
A KSeF integration connects your system to the API of Poland’s National e-Invoicing System. Since 1 February 2026 every taxpayer receives invoices through KSeF, and the Ministry of Finance confirms that software can fetch them automatically. I build these flows: fetching invoices, passing the data to a spreadsheet, CRM or ERP, alerts for unusual items and an archive.
What I can build
Automatic invoice fetching
The flow connects to the KSeF API, regularly checks for new cost invoices and files them in your company archive. Nobody has to log in or download files.
Invoice data where you work
Seller, items and amounts land in a spreadsheet, CRM or accounting system. An AI model can assign a cost category and flag items for review.
Alerts and control
A notification when an invoice comes from a new supplier or the amount differs from usual. Fewer surprises at month end.
Tools for accounting offices
An overview of many clients at once and who is blocking settlements. I’m building such a tool myself: KSeF Control Desk, a dashboard for accounting offices (in the works).
How the rollout works
Flow analysis
We map where invoices come from, where they should go and who approves them. I check which KSeF permissions and access data are needed.
Flow and testing
I build the integration and test it first in the KSeF test environment provided by the Ministry of Finance, then on real invoices.
Launch and support
The flow runs on your account and your data. You get documentation and support when the rules or the API change.
This service is part of a wider offer. Need a website, an app or a system too? See all IT services
KSeF in 2026: what to know
Receiving invoices applies to everyone
The obligation to receive invoices in KSeF has applied since 1 February 2026, including companies that don’t issue invoices in the system yet. Issuing became mandatory on 1 February 2026 for the largest taxpayers and on 1 April 2026 for everyone else, with exceptions until the end of 2026 (for example for sales up to PLN 10,000 a month).
Penalties from 2027, preparation now
The Ministry of Finance postponed penalties for KSeF errors to 1 January 2027. It’s a good moment to make invoice handling automatic, with no retyping, before mistakes start to cost money.
Questions about KSeF integration
Can invoices be fetched from KSeF automatically?
Yes. The Ministry of Finance explicitly confirms that the system allows integrations that fetch invoices automatically. The integration connects to the KSeF API on behalf of your company and saves new invoices where you need them.
What does the integration need to work?
Access to KSeF in your company’s context (tax ID) and an authentication method for the system: a KSeF token or a KSeF certificate. In 2026 both methods work in parallel. I help with granting permissions, but the access data always stays with you.
My accounting software supports KSeF. Why would I need an integration?
Often you don’t. It makes sense when invoices need to go further than the accounting software: to a cost spreadsheet, CRM, warehouse system or an approval process, or when you want alerts and reports your software doesn’t provide.
How much does a KSeF integration cost?
I price it by my price list: a simple automation, such as fetching invoices into a spreadsheet, from PLN 1,500 net, and an integration with a company system (API, ERP) from PLN 10,000 net. You get the fixed price in writing within 48 h of a free call. Details: pricing.
Do you work with accounting offices?
Yes. Offices have a particular problem: many clients, many contexts and invoices that need collecting fast. I build overview and automation tools for them. How invoice fetching works is described in a guide (in Polish): KSeF in practice.
What should I build for you?
Tell me what you want to build or what slows you down. I usually reply the same day, within 24 h at the latest. After a free 30-minute call you get a written fixed-price quote within 48 h.
Prefer skipping the form?
+48 575 885 101m.manka@mankasoft.comWorking hours: Mon–Sat 9:00–17:00, Polish time.