Knowledge Base

KSeF 2026 Questions and Answers

Ponad 100 pytań i odpowiedzi o Krajowym Systemie e-Faktur. Wszystko co musisz wiedzieć o KSeF w jednym miejscu.

Key KSeF Implementation Dates

JAN 2026
KSeF 2.0 launch
FEB 2026
Large companies
APR 2026
Companies >10k PLN
JAN 2027
Everyone

KSeF Basics

9 questions
KSeF (National e-Invoice System) is a central IT system operated by the Ministry of Finance, enabling the issuance, transmission, and storage of structured invoices in XML format. The system ensures invoice standardization, automatic archiving for 10 years, and easier tax control. It can be compared to an "invoice bank" - each invoice sent to KSeF receives a unique identification number and is immediately visible to the issuer, recipient, and tax authorities.
Faktura ustrukturyzowana to faktura w formacie XML zgodnym ze schemą FA(3) opublikowaną przez Ministerstwo Finansów. Zawiera wszystkie wymagane dane w ustandaryzowanej strukturze, co umożliwia automatyczne przetwarzanie przez systemy informatyczne. Nie ma "wyglądu" w tradycyjnym sensie - programy generują na jej podstawie wizualizację w czytelnym formacie.
The main goal is to seal the tax system and prevent fraud. For businesses, this means greater security (invoices won't get lost), potential reduction in bureaucracy (e.g., regarding JPK files), and a step toward full digitalization of document flow in the company.
Yes, invoices issued through KSeF have the same legal force as paper and electronic invoices. Once the obligation comes into effect, KSeF invoices will be the only permitted form of invoicing in B2B transactions for most VAT taxpayers.
Yes. KSeF uses advanced security mechanisms: transmission encryption, token authorization, qualified certificates, or trusted profile. All invoices are stored on Ministry of Finance servers for 10 years.
A KSeF number is a unique invoice identifier assigned by the system after its approval. It consists of 35 characters and uniquely identifies the invoice throughout the entire system. This number is required for corrections and references to invoices.
Yes, an internet connection is required to send an invoice to KSeF. However, mpFaktura allows you to prepare invoices offline and send them to KSeF when a connection is available. In emergency mode (e.g., KSeF outage), you can issue invoices outside the system.
An invoice in KSeF is an XML file with a strictly defined structure. It doesn't have an "appearance" in the traditional sense. Software (both government and commercial) generates a visualization based on it - a so-called transform in a human-readable HTML or PDF format. Such visualization includes a QR code and KSeF number, which allow verification of the document's authenticity.
KSeF does not cover: businesses selling exclusively to private individuals (B2C transactions), companies with monthly revenues below 10,000 PLN gross (until the end of 2026), persons conducting unregistered business activity (until the end of 2026), and issuing simplified invoices (receipt with tax ID up to 450 PLN) from fiscal cash registers (until the end of 2026).

Deadlines and Obligations

8 questions
The KSeF obligation is introduced in stages: from February 1, 2026 for the largest companies (revenues > 200 million PLN in 2024), from April 1, 2026 for other B2B companies (revenues > 10,000 PLN gross monthly), and from January 1, 2027 for micro-businesses and unregistered activity. IMPORTANT: The obligation to receive invoices from KSeF applies to all businesses from February 1, 2026, if they receive an invoice from a large company.
KSeF 2.0 to nowa wersja systemu uruchomiona w styczniu 2026 r. Wprowadza wiele usprawnień: obsługę załączników do faktur, lepszą wydajność, nowy format schematu FA(3)oraz poprawione API. Stary KSeF 1.0 został wygaszony we wrześniu 2025 r. Wszystkie programy mpFaktura są już dostosowane do docelowej wersji KSeF 2.0.
The deadline depends on company size: large enterprises (over 200 million PLN turnover in 2024) from February 1, 2026, other active VAT taxpayers with turnover above 10,000 PLN monthly from April 1, 2026, and micro-businesses, VAT-exempt companies and new taxpayers from January 1, 2027.
Do końca 2026 r. Ministerstwo Finansów nie przewiduje kar za błędu związane z KSeF. Po zakończeniu okresu przejściowego zaczną obowiązywać sankcje finansowe za naruszenie zasad KSeF.
Yes, KSeF has been available voluntarily since 2024. You can already test the system and get used to the new procedures. mpFaktura offers full KSeF support, so you can start issuing structured invoices without waiting for the mandate.
Invoices are stored in KSeF for 10 years from the end of the year in which they were issued. After this period, they are automatically deleted from the system. We also recommend local archiving of invoices in the mpFaktura program.
No, the deadlines remain unchanged. The general rule is still to issue an invoice by the 15th day of the month following the month of delivery/service. KSeF also does not change the moment when the tax obligation arises.
February 1, 2026 - KSeF mandatory for the largest companies (>200 million PLN), all businesses must be ready to RECEIVE invoices. April 1, 2026 - KSeF mandatory for B2B companies with revenue >10,000 PLN/month. January 1, 2027 - KSeF mandatory for micro-businesses and unregistered activities, end of tokens (certificates required), obligation to include KSeF number in payment reference.

Preparing for KSeF

8 questions

Start with an audit of your own company. Ask yourself:

  • 1.How do I issue invoices today? (Paper, Excel, software?)
  • 2.How do I receive invoices today? (Email, mail, in person?)
  • 3.Will my current software be integrated with KSeF? Then choose the right tool, such as mpFaktura, which is fully ready for KSeF.
KSeF is an IT system, not a physical location. You access it through a web browser by logging into the appropriate Ministry of Finance website. You won't receive any letter with a password. Authentication is done using Trusted Profile, qualified signature, or company seal. However, it's most convenient to use it through invoicing software like mpFaktura.

The connection is very simple and one-time. You need to:

  • 1.Download the latest version of mpFaktura.
  • 2.Enable KSeF support and select the appropriate schema version - FA(3).
  • 3.Authenticate in KSeF directly from the application.
  • 4.Generate KSeF certificate and offline certificate.
A token is used to authenticate commercial software in KSeF. It's a transitional solution, valid until the end of 2026. A certificate is a more advanced and secure authentication method that will replace tokens from 2027. It will also be necessary for issuing invoices in offline mode (during KSeF outages).
You don't create an "account" in the traditional sense. If you're a business owner, you log in with your credentials (e.g., Trusted Profile) and the system automatically recognizes your company. Even if the obligation to issue invoices applies to you only in 2027, from February 1, 2026, you must be ready to receive invoices.
  • 1.Diagnose your situation: How do you issue and receive invoices?
  • 2.Choose a tool: Test mpFaktura with a free 30-day trial period.
  • 3.Configure the connection: Generate a token and connect the software with KSeF.
  • 4.Test: Send a few test invoices, download purchase invoices.
  • 5.Train your team: Make sure everyone knows how to use the new system.
  • 6.Establish procedures with your accounting office.

This is a key element of implementation. You should:

  • 1.Train the team on changes and new procedures.
  • 2.Designate people responsible for invoicing and document receipt.
  • 3.Grant them appropriate permissions in KSeF.
  • 4.Create internal document workflow procedures.
  • 5.Conduct tests on the demo version of KSeF or in mpFaktura software.
mpFaktura offers data import from popular formats (CSV, XML). You can import: contractor database, product/service database, and optionally historical invoices. Contact us and we'll help with data migration.

Issuing Invoices

14 questions
In KSeF you can issue: standard VAT invoice (for VAT payers and exempt entities), credit note, advance invoice and advance settlement invoice, VAT margin invoice, VAT RR invoice (for lump-sum farmers), and simplified invoice (currently voluntary).
You cannot issue in KSeF: proforma invoices (these are commercial offers, not accounting documents), credit notes, debit notes, internal documents, or receipts (as defined by the Tax Ordinance Act). These documents are still issued outside KSeF, e.g., in mpFaktura.
The following will disappear: credit notes (every mistake, even a typo in the address, will need to be corrected with a corrective invoice), invoice duplicates (invoices are stored in KSeF for 10 years, so they can always be downloaded), invoice cancellation (an incorrectly sent invoice cannot be deleted - it will need to be corrected "to zero").
  • 1.Launch the mpFaktura software.
  • 2.Issue an invoice - just as you have done before.
  • 3.Change the invoice status to: "Approved".
  • 4.Click: "Send to KSeF". The invoice will be validated, converted to XML format, and sent to KSeF. Upon acceptance, you will receive a UPO with the KSeF number.
An invoice for a foreign EU company is issued in KSeF. The foreign recipient will not be able to log into KSeF and download the invoice, so the seller must provide the document to the contractor in another way, e.g., as a PDF via email. The invoice should include a QR code that allows verification that the document actually exists in KSeF.
Similar to EU companies. You issue the invoice in KSeF, then send it to the client via email as a PDF or provide it in another agreed format. mpFaktura automatically generates a PDF with a QR code for verification.
Such an invoice must be sent to KSeF. mpFaktura supports foreign currency invoices. You enter amounts in the foreign currency, and the system automatically converts them to PLN using the NBP exchange rate from the day preceding the invoice issue date.
Yes, but with limitations. The invoice issue date can be earlier than the date of sending to KSeF, but must comply with regulations on invoice issuance deadlines. Both the issue date and the date of submission to the system will be visible in KSeF.
Each line item on the invoice can have a different VAT rate. In mpFaktura, you add subsequent items, selecting the appropriate rate for each (23%, 8%, 5%, 0%, exempt, etc.). The system automatically calculates the summary for each rate.
When adding a line item to the invoice in mpFaktura, fill in the "Discount (%)" field by entering the appropriate percentage value. The system will automatically calculate the discounted price.
Yes, mpFaktura enables batch invoice submission, which is crucial for companies issuing many documents. You can also set up automatic sending at a specified time.
An invoice sent to KSeF is considered delivered. The client can download it themselves by logging into KSeF. However, for convenience, you can: send the client an email notification with a link to the PDF visualization (feature available in mpFaktura) or download the invoice as PDF and send it traditionally via email.
No. Invoices for consumers (individuals not conducting business) do not need to be sent to KSeF. You can issue them in the traditional way in mpFaktura.
Yes, from KSeF version 2.0 onwards, you can attach files to invoices (e.g., specifications, acceptance protocols). Attachments must be in PDF format and cannot exceed 10 MB. mpFaktura allows adding attachments before sending the invoice.

Invoice Corrections

9 questions
You issue a corrective invoice when: you made a mistake in the data (name, address, tax ID number), the price or quantity of goods/services changed, the client returned goods, you granted a discount after issuing the invoice, or the invoice should not have been issued at all (correction "to zero").

In mpFaktura:

  • 1.Select the document you want to correct.
  • 2.Enter the corrected data (e.g., new quantity, price, VAT rate).
  • 3.Change the correction status to "Approved".
  • 4.Click: "Send to KSeF". The correction must include the KSeF number of the corrected invoice - mpFaktura fills this in automatically.
You issue a corrective invoice in which all corrected items are set to a value of 0 PLN. In the "reason for correction" field, you enter e.g., "Incorrectly issued invoice" or "Transaction cancellation". mpFaktura simplifies this process by automatically generating a zero-value correction.
Yes. In the corrective invoice, you only include the items that require correction. Other items do not need to be included.
You issue a corrective invoice with the correct buyer data. In the "reason for correction" field, you enter e.g., "Correction of buyer's address data".
You must issue a corrective invoice. There is no option to cancel an invoice in KSeF. If the invoice was issued to a completely different company, you issue a correction "to zero" and a new invoice with the correct data.
Yes. If the corrective invoice also contains an error, you issue another correction. In practice, however, it's better to issue one correct correction to the original invoice.
There is no strict deadline, but the correction should be issued immediately after discovering the error. For tax purposes, it's important in which settlement period the correction affects VAT.
Invoices in KSeF cannot be deleted or canceled. Once sent, they become part of the official document flow. The only solution is to issue a credit note. Therefore, it's worth carefully checking invoices before sending them.

Receiving Invoices

8 questions
Invoices issued to your tax ID number will automatically be waiting for you in KSeF. You can download them: manually, by logging into the government application, or automatically, using mpFaktura software, which will download invoices from KSeF, save them in your database, and allow you to preview these documents.
No. The appearance of an invoice in KSeF does not mean it has been posted. You still need to pass it to your accounting department or manually enter it into your records (e.g., revenue and expense ledger). mpFaktura facilitates this process by allowing data export to accounting systems.
We recommend daily or weekly checks. mpFaktura can automatically download new invoices, eliminating the need for manual checking. You can set the synchronization frequency.
W mpFaktura ustawiasz filtr dat (np. 01.01.2026 - 31.01.2026) i pobierasz wszystkie faktury spełniające kryteria. Możesz podejrzeć ich podgląd w formie tzw. transformaty. Dokumenty możesz m.in. zapisać do PDF.

Check:

  • 1.Whether the contractor actually sent the invoice to KSeF (and not just issued it in their software).
  • 2.Whether the invoice was issued to the correct tax ID number.
  • 3.Whether there is a synchronization delay (refresh the invoice list in mpFaktura).
In such a case, immediately contact the invoice issuer and request a credit note to zero. In case of attempted fraud, report it to the appropriate authorities.

You have several options:

  • 1.Grant permissions - the accountant will download invoices from KSeF themselves.
  • 2.Export to XML - download invoices and send XML files by email.
  • 3.Shared software - use the same software (e.g., mpFaktura Online), where the accountant has access to your documents.
From January 1, 2027, when paying for an invoice issued in KSeF to another VAT taxpayer, you will need to include the KSeF number of that invoice in the transfer title. In 2026, there is no such requirement yet. mpFaktura makes it easy to copy the KSeF number.

Permissions and Accounting Office

11 questions
No. As the owner, you have full permissions, but you can (and should) grant them to other people. You can authorize: an employee (e.g., to issue invoices), a spouse (e.g., to manage permissions), an accounting office/accountant (e.g., to download sales and expense invoices).
You can grant very detailed permissions, including: issuing invoices, viewing invoices (sales and purchase), managing permissions (delegating permissions to others), viewing session history (downloading UPO), self-invoicing (when the client issues an invoice on our behalf).

In mpFaktura:

  • 1.Go to "Management" -> "KSeF Management".
  • 2.Go to the "Settings" tab and in the "General Options" section, specify the users responsible for downloading documents from KSeF, checking statuses/UPO, and sending documents.
In mpFaktura, go to permission management and revoke the previously granted permission from the employee. Important: permissions remain active until you revoke them. Therefore, immediately revoke permissions from a former employee after the end of cooperation.
Only if you grant them the "Permission Management" permission. Then they can grant and revoke permissions to other people on your behalf.

KSeF revolutionizes this cooperation. The most popular models are:

  • 1.Working together on one software - The office provides you with software where you both have access to documents.
  • 2.The office issues invoices for you - You provide the data, and they issue invoices on your behalf.
  • 3.You issue, the office downloads - You issue invoices in mpFaktura, and the office independently downloads them from KSeF.
It's best to grant permissions to the entity (to the accounting office's tax ID number), not to a specific individual. This gives the office the ability to further delegate permissions to its employees. When you end the cooperation and revoke the office's permissions, the permissions granted by the office to its employees will also automatically expire.
Most commonly: viewing invoices (so they can download sales and expense invoices), issuing invoices (if the office is to issue invoices on your behalf), optionally: the ability to further grant permissions to office employees.
Only if you grant them the appropriate permissions. You can grant permission only to view purchase invoices (expense invoices), without access to sales invoices. The scope of permissions depends on you and your arrangements with the office.
  • 1.Revoke permissions from the current office.
  • 2.Grant permissions to the new office.
  • 3.Provide the new accounting office with necessary information about existing documentation.
No. When granting permissions, you cannot specify an expiration date. However, you can revoke permissions at any time.

Technical Aspects

9 questions
An authorization token is a unique string used for authentication in the KSeF API. It is generated in the KSeF Taxpayer Application or by invoicing software. The token enables automatic communication with the system without logging in each time. Tokens will remain valid until the end of 2026.
KSeF supports several authorization methods: trusted profile (ePUAP), qualified certificate, electronic seal, and authorization tokens. In mpFaktura, you can use a token, which is the most convenient method for daily work.
UPO (Official Acknowledgement of Receipt) is confirmation that an invoice has been accepted by KSeF. It contains the KSeF number, date, and time of acceptance. mpFaktura automatically downloads the UPO after sending an invoice and stores it with the document.
After sending an invoice, you receive a UPO (Official Acknowledgement of Receipt). This is a document confirming that the invoice has been accepted by the system and assigned a KSeF number. The UPO can be downloaded from the KSeF application or from mpFaktura.
There is no such requirement. Invoices are stored in KSeF for 10 years. You can download them at any time. Printing is optional, for example, if the client requires it.
Regulations provide for an emergency mode. If KSeF is not working, you can issue an invoice outside the system in mpFaktura. Such an invoice will be marked with a special QR code. After the system is restored, you will have a specified time to send this invoice to KSeF. mpFaktura handles this process automatically.
  • 1.You issue an invoice in mpFaktura.
  • 2.The software marks the invoice with a special QR code and an offline mode annotation.
  • 3.After access to KSeF is restored, you send the invoice to the system. An offline invoice is a valid document from the moment of issuance.
It depends on the reason for unavailability: no internet (24h) - by the end of the next business day, planned technical maintenance - deadline specified by the Ministry of Finance, system failure - deadline specified after service is restored.
The Ministry of Finance publishes announcements about planned outages and failures. You can also check the status on the KSeF website or in mpFaktura, which automatically detects system unavailability.

mpFaktura and KSeF

9 questions
Yes, mpFaktura has been fully integrated with KSeF since November 2025. We support the latest KSeF 2.0 format with all features: invoice submission, downloading purchase invoices, automatic UPO, corrections, attachments, and emergency mode.
In the top menu, go to Settings → Integrations → KSeF. Generate an authorization token in the KSeF Taxpayer Application and paste it in the configuration field. You can also use a qualified certificate or trusted profile.
Yes, the Ministry of Finance provides a test (demo) environment for KSeF. In mpFaktura, you can switch between production and test environments in the integration settings. We recommend testing all scenarios before going live.
Tak, mpFaktura przeprowadza pełną walidację faktury przed wysłaniem do KSeF. Checkamy zgodność ze schemą FA(3), poprawność NIP, wymagane pola i formaty danych. Dzięki temu minimalizujemy ryzyko odrzucenia faktury przez system.
After issuing an invoice, click the "Send to KSeF" button or enable automatic submission in settings. The invoice will be validated, converted to XML format, and sent to KSeF. Upon acceptance, you will receive a UPO with the KSeF number.
Yes, you can enable automatic downloading of purchase invoices in KSeF settings. mpFaktura will regularly check for new invoices and import them into the purchases module. You can also manually download invoices for a selected period.
Yes, the mpFaktura app for iOS and Android supports KSeF. You can issue and send invoices to KSeF directly from your phone or tablet. An internet connection and configured authorization token are required.
When mpFaktura detects KSeF unavailability, it automatically switches to emergency mode. Invoices are issued with the appropriate annotation and queued for submission. After KSeF resumes operation, the system automatically sends pending invoices.

The process is intuitive:

  • 1.You authenticate in KSeF.
  • 2.You issue an invoice as usual in the software.
  • 3.You click "Send to KSeF" - the invoice is submitted to the system and receives a number.
  • 4.You can download purchase invoices automatically or manually.

Settlements and Accounting

7 questions
Yes, KSeF invoices must be included in JPK_VAT. The date of invoice acceptance by KSeF is the issue date for tax purposes. mpFaktura automatically generates JPK_V7M/V7K including KSeF invoices.
mpFaktura offers invoice export to popular accounting software: Comarch Optima, Insert (Rachmistrz, Rewizor), Wapro Fakir, R2KSIĘGA. The export includes KSeF numbers and all required data. Go to the Start menu → Export Data.
Yes, purchase invoices downloaded from KSeF give the right to VAT deduction under general rules. The fact that an invoice has been accepted by KSeF is additional confirmation of its authenticity. mpFaktura automatically imports purchase invoices from KSeF.
Go to Tools → JPK Archive and Submission → Generate JPK_FA. Select the period and invoice type. mpFaktura automatically includes KSeF numbers and required fields. You can submit JPK directly to the tax office.
Yes, self-billing is supported by KSeF. The buyer can issue an invoice on behalf of the seller if there is an appropriate agreement. mpFaktura enables issuing invoices on behalf of a contractor with full KSeF support.
Split payment is a mechanism where the buyer pays the net amount to the seller's account and VAT to a special VAT account. In KSeF, an invoice can contain a note about mandatory split payment for specific goods/services. mpFaktura supports marking invoices for split payment.
No. KSeF is an invoicing system, not a payment system. Payment verification takes place in banking and accounting systems. You manage payment status in mpFaktura, which can track receivables and payables.

Special Cases

11 questions
Until the end of 2026, you don't have to issue invoices through KSeF. From January 1, 2027, you will have to do so if you issue invoices to businesses. Starting February 1, 2026, you must be ready to receive invoices from KSeF if you buy from large companies. Perfect solution: mpFaktura with a 30-day free trial period.
Yes. The KSeF obligation applies to all entrepreneurs issuing invoices to businesses, regardless of VAT status. As VAT exempt, you issue invoices with the rate "zw" (exempt) or "np" (not applicable). The process is the same.
Each business has a separate tax ID number and is treated as a separate entity in KSeF. You log in to KSeF by providing the tax ID number of a specific company. mpFaktura allows you to manage multiple companies on one license - you can handle each in a separate database.
Foreign currency invoices are fully supported by KSeF. You must specify the currency (e.g., EUR, USD), exchange rate, and rate source (e.g., NBP). mpFaktura automatically downloads current exchange rates and fills in the required fields.
No, proforma invoices are not sent to KSeF. A proforma is not an accounting document and is not subject to the KSeF obligation. Only the final invoice issued based on the proforma must be sent to the system.
Fiscal receipts are not sent to KSeF. However, if a customer requests an invoice for a receipt, such an invoice must be issued through KSeF. mpFaktura enables generating invoices for receipts with automatic submission to KSeF.
Yes, VAT RR invoices are subject to the KSeF obligation from the moment the regulations come into force for a given group of taxpayers. mpFaktura supports RR invoices with full KSeF integration, including specific fields for farmers. The buyer (VAT taxpayer) will issue a VAT RR invoice in KSeF only if the flat-rate farmer submits a declaration in the system.

Advance invoices are sent to KSeF like regular invoices. In mpFaktura:

  • 1.Select document type - "Advance invoice".
  • 2.Specify the buyer and add items.
  • 3.Enter the advance amount.
  • 4.Change status to "Approved".
  • 5.Click "Send to KSeF". The system will calculate VAT only on the advance amount.

In mpFaktura:

  • 1.Open the document for which you want to issue a final invoice.
  • 2.Click "Next advance".
  • 3.Check the "Final advance" option.
  • 4.The system will automatically deduct previously paid advances and calculate the amount due.
  • 5.Change status to "Approved" and send to KSeF.
Yes, invoices issued to foreign contractors (intra-Community supply, export of services) are subject to the KSeF obligation. The foreign recipient does not need to have access to KSeF – the invoice can be provided to them in traditional form (PDF, printout) with a QR code for verification.
If your contractor is not yet subject to the KSeF obligation (e.g., has revenue below PLN 10,000), you can send them the invoice traditionally (by email, mail). The invoice still must go to KSeF (if you are subject to the obligation), but the contractor can receive it from you in PDF form.

Integrations and E-commerce

6 questions
Yes, mpFaktura imports orders from Allegro and automatically generates invoices. If you have KSeF integration enabled, invoices for Allegro orders are sent to KSeF like any other invoice.
mpFaktura retrieves orders from BaseLinker (which supports multiple e-commerce platforms) and generates invoices. After issuance, the invoice is automatically sent to KSeF. The KSeF number can be passed back to BaseLinker.
Yes, in addition to sending the invoice to KSeF, you can also send the customer a PDF visualization by email. mpFaktura generates a readable PDF version of the KSeF invoice with the KSeF number and QR code for verification in the system.
Orders imported from WooCommerce are processed in mpFaktura as usual. After the invoice is generated, it is automatically sent to KSeF. The invoice link can be updated in WooCommerce for the customer.
Yes. mpFaktura offers automatic sending of invoices to KSeF after they are issued. You can also set up batch sending at a specific time, which is ideal for companies issuing many documents.
Yes. mpFaktura can automatically download new purchase invoices from KSeF and save them in the database. You can set the synchronization frequency according to your needs.

Security and Privacy

5 questions
Yes. KSeF is a government system with a high level of security. Access requires authentication (via one of the selected methods: Trusted Profile, company seal, qualified signature). Invoices are stored for 10 years.
Access is granted to: You as the business owner, people you have authorized, and tax authorities (Tax Office, Ministry of Finance).
No. Invoices are visible only to the issuer, recipient, and tax authorities. Competitors do not have access to your documents.
  • 1.Do not share your token/certificate with third parties.
  • 2.Regularly check the list of authorized persons.
  • 3.Revoke access for former employees.
  • 4.Use strong passwords for your Trusted Profile.
  • 5.Use trusted software like mpFaktura.
In mpFaktura, you can check the session history and see who issued a given invoice and when. This feature is important for control and audit purposes.

Common Mistakes

3 questions
  • 1.Incorrect buyer's tax ID number - always verify the tax ID before issuing an invoice.
  • 2.Failure to send to KSeF - make sure the invoice reached the system.
  • 3.Incorrect VAT rate - check the rate for the given product/service.
  • 4.Missing bank account number - add it if you expect a bank transfer.
  • 1.Test before launch - send a few test invoices in the demo environment.
  • 2.Train employees - make sure everyone knows the procedures.
  • 3.Update your software - use the latest version of mpFaktura.
  • 4.Check UPO - verify that invoices reached KSeF.
  • 5.Carefully check data before sending - invoices cannot be canceled.
Read the error message - it usually concerns: incorrect data format, missing required fields, or incorrect numbers (tax ID, bank account). mpFaktura validates invoices before sending, so most errors are caught earlier. Correct the data and resend.

Prepare your business for KSeF 2026

mpFaktura jest w pełni gotowa na obowiązkowe e-faktury. Zacznij już dziś i przetestuj integrację z KSeF za darmo.

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