Free online invoicing software
with KSeF support
Logging into KSeF is an early step before working with structured invoices. Access is not a conventional username and password account: identity must be confirmed through Trusted Profile, qualified signature, qualified seal, token or KSeF certificate. We explain the steps, method selection and access for employees, partners and accounting firms.
What is KSeF and why does login matter?
The National e-Invoicing System is a Ministry of Finance platform for issuing, sending, receiving and storing structured invoices. It becomes mandatory for successive groups from 2026. Unprepared companies may face serious day-to-day invoicing difficulties.
Owning a business does not automatically grant access. First authenticate your identity and right to act for the taxpayer. Key dates:
- 1 February 2026: issuing obligation for companies with 2024 gross sales above PLN 200 million.
- 1 April 2026: other businesses.
- Until year-end 2026: concession for taxpayers whose invoices outside KSeF do not exceed PLN 10,000 monthly.
Testing access before the deadline helps avoid costly downtime.
Where can you log in?
Several official channels exist, depending on everyday invoice handling.
The free KSeF 2.0 Taxpayer Application issues, receives and displays invoices through a browser, providing the full system functionality for businesses not using commercial invoicing software.
Financial accounting software integrated with the KSeF 2.0 API: most commercial ERP and invoicing systems offer or develop integration. Login happens in the software, which automatically passes certificates, tokens or signatures.
The KSeF Mobile Application simplifies smartphone handling, particularly invoice viewing and receipt away from the office.
e-mikrofirma in the e-Tax Office is another option for selected users of digital tax administration services.
Important: use only official Ministry addresses and applications listed at podatki.gov.pl. Never enter credentials on uncertain sites, especially general search results.
Login step by step
These instructions use the Taxpayer Application, the most universal route for independent invoice management.
1. Open the application
Visit the official KSeF 2.0 Taxpayer Application. It runs in the browser without installation. The start screen offers login and method selection.
2. Choose authentication
There is no ordinary username/password login. Choose:
- Trusted Profile / login.gov.pl: free for individuals, including sole traders, with online banking among the login options.
- Qualified signature: paid, requiring a qualified electronic signature containing NIP or PESEL. Otherwise its fingerprint must first be registered.
- Qualified seal: for non-individual entities such as companies, linked to the entity rather than a person.
- KSeF certificate: available through the API and application from February 2026, obtained after prior taxpayer or authorised-person login.
- Token: mainly for ERP and accounting integrations. The Ministry says tokens work until the end of 2026 and are to be replaced by certificates.
3. Confirm identity
Trusted Profile redirects to login.gov.pl for bank or mObywatel confirmation. Qualified signatures and seals need appropriate software and a cryptographic card. Successful authentication returns you to KSeF.
4. Select company context
Check the correct context. With several entities or personal and company access, you may choose individual taxpayer, sole trader or company-authorised person. Available invoices and functions depend on it.
5. Check functions
In the correct context you can:
- Issue structured invoices.
- Receive supplier invoices.
- Browse and search issued and received documents.
- Download XML or PDF invoices.
- Download official receipt confirmations, UPO.
- Manage employee and accounting firm permissions.
- Request and manage certificates.
- Generate and manage tokens until year-end 2026.
Trusted Profile login
This is the simplest free method, convenient for sole traders and individuals. Create a profile through online banking, ZUS or a tax office.
“Log in with Trusted Profile” redirects to login.gov.pl, where SMS, a banking app or mObywatel confirms identity. The system returns automatically to an authenticated KSeF session.
It works well for individuals but may not suffice for companies or advanced access management. A seal, signature or certificate may be preferable.
Qualified signature login
This paid method comes from qualified trust providers such as Certum, EuroCert, Sigillum and KIR. It suits owners already signing contracts or tax declarations.
The signature must contain the owner’s NIP or PESEL. Without them, register its fingerprint before the first login or KSeF cannot link it to the taxpayer.
Install signature software and connect a cryptographic card or USB token.
Qualified seal login
This is important for companies and other non-individual entities. Unlike a personal signature, the seal belongs to the company.
It permits direct company login without naming an individual representative, convenient for larger finance departments or external accountants.
Without a seal, designate an authorised person through ZAW-FA or the relevant KSeF procedure. They then use their signature or Trusted Profile in the company context.
KSeF certificates
From February 2026, requesting, downloading and managing certificates is possible through the KSeF 2.0 API and Taxpayer Application.
There are two types:
- Type 1: authentication and online invoicing.
- Type 2: offline invoicing without a current server connection.
First log in as taxpayer or authorised person, for example with Trusted Profile or signature, then apply in the Certificates and Permissions Module, MCU.
Certificates permit issuing and receiving company invoices. Only designated trusted people should access them. Giving one to an unauthorised person amounts to giving full access to company invoicing.
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Can you still use a KSeF token?
A token is a character string authenticating external accounting software, ERP or custom API integrations. It was long the main connection method.
The Ministry says tokens work only until year-end 2026, after which certificates are intended as the main integration method.
In practice:
- Ask software providers whether and when they plan certificate migration.
- Do not create long-term integrations relying solely on tokens.
- Generation, viewing and revocation still take place in the Taxpayer Application.
Sole trader login
The owner acts as an individual linked to the business NIP, without needing designation or extra forms for access.
The simplest route:
- Open the Taxpayer Application.
- Use Trusted Profile or a qualified signature.
- Check the displayed business NIP.
- Grant MCU permissions if staff, accountants or others handle invoices.
Trusted Profile generally suffices, but ask integrated invoicing software providers which method they require.
Company login
A company cannot log in “personally”: a natural or legal person acts on its behalf. Plan the access structure first.
Checklist:
- Who administers access?
- Does the company have a qualified seal?
- If not, is someone authorised through ZAW-FA or MCU?
- Who issues and receives invoices?
- Does an internal department, employee, board or external accountant handle them?
- Is software integrated with KSeF 2.0?
- Is there a procedure to remove access when people leave?
Routes include:
- The entity’s seal, directly on behalf of the company.
- An authorised representative’s qualified signature.
- An authorised person’s Trusted Profile after correct permission assignment.
Granting staff and accountants access
Owner access is only half the process. Others handling invoices need permissions.
Since 1 November 2025, new permissions are assigned through MCU and can cover:
- Issuing and sending invoices for the company.
- Receiving purchase invoices.
- Viewing only, without issuing.
- Granting and revoking others’ access: administrative permission requiring caution.
- Requesting, downloading and revoking certificates and tokens.
An accounting firm should receive only necessary permissions. The owner is responsible for assignments; errors may allow unauthorised viewing or issuing.
If uncertain, organise access before mandatory invoicing. Errors may hinder issuing and receiving at a critical moment.
Which method should you choose?
| Situation | Usually suitable method |
|---|---|
| Sole trader owner | Trusted Profile or qualified signature |
| Company with seal | Entity’s qualified seal |
| Company without seal | Person authorised through ZAW-FA or MCU |
| Accounting / ERP software | Certificate, qualified signature or seal; token until year-end 2026 |
| Accounting firm | Client-granted MCU access |
| Offline / network failure | Type 2 certificate |
| Finance employee | Owner or administrator permissions |
Common login problems
Before calling the Ministry helpline, check:
- Missing permissions: authentication works but invoices are absent; verify owner-granted access.
- Wrong context: individual rather than company or business NIP.
- No NIP/PESEL in the signature: register the fingerprint.
- Outdated access: expired or revoked token.
- Seal problems: expired certificate, missing software or card issue.
- System maintenance: check official Ministry status.
- Unofficial page: verify the browser address.
- No designated administrator to grant or remove access.
- Certificate not downloaded or correctly installed.
Login and data security
All company invoices pass through KSeF. Treat access as seriously as a business bank account.
Basic rules:
- Do not give tokens, certificates or credentials to anyone you do not fully trust.
- Do not enter credentials on unverified sites.
- Review MCU permissions and users regularly.
- Remove access promptly when people stop invoice work or leave.
- Set responsibility and procedures for lost certificates or tokens.
- Remember that a captured certificate permits company invoice issuing and may have serious legal and financial consequences.
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Summary
KSeF access combines identity confirmation, company context and permissions. Choose a method suited to the owner, company and software, test it in advance and assign only necessary rights. Regular access reviews and a removal procedure help protect invoice data and continuity.
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