The National e-Invoice System (KSeF) is a revolution that is transforming the way companies issue and receive invoices. For corporations and large organizations, the process of “onboarding” to the system may seem complicated, but there is a shortcut. If your organization has a qualified electronic seal, you can skip the trips to government offices and the paperwork.
At podpisano.pl simple solutions, which is why we’ve prepared a step-by-step guide on how to register (authenticate) in the system using a digital seal.
Today, in the digital world, a qualified digital seal is the equivalent of a company stamp and a representative’s signature, but in a virtual form. The key difference between it and a personal signature is that the seal contains the entity’s (company’s) details, including its tax identification number.
This allows the KSeF system to automatically recognize your company. You do not need to submit a paper ZAW-FA notification to the tax officeto designate the first person authorized to use the system. You simply “log in” to the system with your company seal and immediately gain full ownership rights.
Before you start clicking, take a look at the procedure. The entire process is based on the “challenge-response” principle. The system issues a digital challenge (a file to be signed), and you send it back with your digital signature.
This process is technically referred to as “authentication.” Here’s what you need to do, based on the official instructions from the Ministry of Finance.
Log in to the app Open your browser (recommended: Chrome, Firefox, Edge, or Safari) and go to the KSeF Taxpayer Application website.
To log in to KSeF, go to https://ap.ksef.mf.gov.pl/web/
Preparation Make sure you have a device or app for creating a qualified digital seal on hand, as well as the software provided by your seal issuer installed. In podpisano.pl you can easily get a qualified seal without waiting in lines or stress.
Select a login method → Log in with a qualified certificate.
Login In the login window, enter your NIP . The system will ask for the login context—make sure you enter the NIP of the entity you want to log in as. Click the Authenticatebutton.
Authorization Request (AuthRequest) This is the most important moment.
Submission of the seal
Upload to KSeF
All done! If the verification is successful, you'll see the app's home screen.
If the authorization is successful, an informational message will be displayed containing the session number.
You can copy the session number by clicking [1] "Copy". The session number is required to verify the shipping status of invoices in a given session.
To close the window, click the [2] "OK" button.
Note! Assuming the file has been signed correctly, clicking the “Next” button will take you to the application with authorization for the tax ID context you selected at the beginning.
Please note that authorization using a signature with a Tax ID number other than the context Tax ID number, or a signature with a PESEL number, requires that permissions be granted for those identifiers in advance.
Once you’re logged in as the “owner” (super-administrator), your goal isn’t to issue invoices this way on a daily basis (it’s too tedious), but to set up the company.
After logging in to the KSeF Taxpayer Application, you will see the invoice entry screen and the application’s main menu. Remember to do the following after your first login:
Using an electronic seal is the fastest way to “activate” your business in KSeF. You avoid trips to the office, and the entire process takes just a few minutes at your computer.
Keep in mind, however, that the seal is primarily used to open doors and for administrative purposes—for day-to-day operations, it’s best to authorize specific employees or IT systems.
If you need help obtaining a qualified digital signature, check out the services available at podpisano.pl
We also invite you to contact podpisano.pl – we will help you secure your company's digital identity.
For more information on KSeF procedures, visit the official website ksef.podatki.gov.pl and in our knowledge base.
This article was prepared based on the KSeF 2.0 Handbook (Ministry of Finance, September 2025) and information from the website ksef.podatki.gov.pl.
