KSeF (National e-Invoicing System) is a major step towards the digitalisation of the Polish economy, allowing structured invoices to be issued and made available in a single, nationwide IT system. The system has been available since 1 January 2022 and until 31 January 2026 it was one of the voluntary ways of documenting transactions, alongside traditional paper invoices and electronic invoices in PDF format.
Mandatory use of structured invoices was introduced in stages – from 1 February 2026 for taxpayers whose sales including tax exceeded PLN 200,000,000 in 2024, and from 1 April 2026 for all other businesses (Article 106ga section 1 and Article 145l of the VAT Act). Until 31 December 2026, taxpayers whose sales documented with invoices in a given month do not exceed PLN 10,000 gross may still issue invoices outside KSeF (Article 145m), and penalties for failing to issue an invoice in KSeF apply from 1 January 2027 (Article 106ni). This change means the end of paper and electronic invoices in their previous form for transactions covered by KSeF, which requires all market participants to prepare properly.
The law expressly allows permissions to issue and access structured invoices to be granted to entities designated by the taxpayer, including accounting offices (Article 106nb of the VAT Act, § 3 section 3 of the regulation on using KSeF). This makes cooperation between businesses and external accounting firms easier and helps maintain continuity of accounting services in the new system
For many business owners, the key question remains how to grant KSeF permissions to accounting offices that have so far issued invoices on their behalf. The system offers flexible solutions that allow permissions to be granted directly to specific employees of accounting offices, as well as authorising whole entities to act on the taxpayer's behalf.
Who can use the National e-Invoicing System
A structured invoice is a document issued using KSeF that receives a unique identification number in the system. It takes the form of an XML file compliant with the logical structure of the e-Invoice – since 1 February 2026 this has been the FA(3) structure (previously FA(2)), published in the Central Repository of Electronic Document Templates on the ePUAP platform.
Various categories of taxpayers use KSeF (since 2026, as a rule, all taxpayers issuing invoices are required to issue structured invoices – Article 106ga section 1 of the VAT Act):
- Active VAT taxpayers running a business
- Businesses that are exempt from VAT
- Taxpayers identified in Poland for the special EU OSS procedure who have a Polish NIP (tax identification number)
Until 31 January 2026, issuing invoices through KSeF was voluntary, and KSeF users enjoyed additional benefits, in particular a VAT refund within 40 instead of 60 days. Since 1 February 2026, the standard refund period has been 40 days for everyone (Article 87 section 2 of the VAT Act)
The VAT refund period no longer depends on using KSeF. The former conditions of this benefit in Article 87 sections 5b–5d of the VAT Act have been repealed, and the 40-day refund period runs from the date the return is filed (Article 87 section 2). Shorter periods still apply, e.g. 25 days if the conditions of Article 87 section 6 are met.
Another important rule concerns settling corrective invoices that reduce the amount ("in minus"). A taxpayer who has issued a corrective invoice as a structured invoice reduces the taxable amount in the settlement period in which it was issued, without confirmation that the buyer has received the correction (Article 29a section 13 of the VAT Act). For a correction issued outside KSeF, the decisive period is the one in which the buyer's confirmation of receipt is obtained (Article 29a section 13a).
The system also standardises invoicing according to a single template, which makes issuing and posting invoices much easier and more efficient. In addition, a structured invoice is received by the buyer through KSeF on the day it is assigned its identification number in the system (Article 106na section 3 of the VAT Act), which limits disputes about whether the document was delivered to the counterparty.
KSeF stores invoices for 10 years from the end of the year in which they were issued (Article 112aa section 1 of the VAT Act). Invoices issued in KSeF are archived in the Ministry of Finance system, which reduces the risk of documents being destroyed or lost and the need to issue duplicates
Types of permissions in the National e-Invoicing System
The rules on permissions to use KSeF are set out in detail in the Regulation of the Minister of Finance and Economy of 12 December 2025 on using the National e-Invoicing System (Journal of Laws (Dz.U.) 2025 item 1815, amended by Dz.U. 2026 item 169), which replaced the Regulation of the Minister of Finance of 27 December 2021 on 1 February 2026. It precisely defines the types of permissions and how they are granted and revoked.
Under § 3 section 1 of the regulation, permissions to use KSeF fall into four categories:
- Granting and revoking permissions to use KSeF
- Issuing or accessing structured invoices (and invoices issued in offline or emergency mode and sent to KSeF)
- Issuing invoices by the buyer of goods or services under Article 106d section 1 of the VAT Act (self-billing)
- Issuing VAT RR invoices and VAT RR KOREKTA invoices using KSeF
| Type of permission | Scope of actions | Who can hold it | How it is granted |
|---|---|---|---|
| Administrative | Granting and revoking permissions | The taxpayer and natural persons designated by them (§ 3 section 2) | Electronically; ZAW-FA only in the cases under § 5 |
| Operational | Issuing and accessing invoices | The taxpayer, designated natural persons or entities | By the taxpayer or a person authorised to grant permissions |
| Special | Invoices under Article 106d section 1 (self-billing) | A buyer designated by the taxpayer and persons designated by that buyer | Granted by the taxpayer to the buyer (§ 3 section 4) |
| Indirect | Issuing or accessing invoices through a third party | An entity designated by the taxpayer (e.g. an accounting office) and natural persons designated by that entity | Electronically, by designating the entity (§ 3 section 3) |
§ 3 sections 2 and 3 of the regulation set out in detail who is entitled to issue or access structured invoices. The list covers not only the taxpayer, but also a wide range of persons and entities acting on their behalf.
Permissions to issue structured invoices may be held by the taxpayer, natural persons designated by the taxpayer, entities designated by the taxpayer and natural persons designated by those entities. An entity designated by the taxpayer (e.g. an accounting office) receives permission to issue or access invoices, but not to grant permissions on the taxpayer's behalf. The system also provides special permissions for the entities referred to in Article 106c of the VAT Act
The flexibility of the permissions system allows businesses to adapt how they manage invoicing to the nature of their activity. This is particularly important for companies using external accounting offices, which can receive the appropriate permissions to act on behalf of their clients.
Procedures for granting permissions
KSeF provides two basic ways of granting or revoking permissions, adapted to the technical capabilities of different categories of users.
The first is the electronic procedure, carried out using interface software (e.g. the KSeF Taxpayer Application or invoicing software), after the permissions held have been verified (§ 4 section 1 of the regulation). Here, the taxpayer or another authorised entity enters the required data directly in the system – including the taxpayer's NIP, the NIP or PESEL (national ID number) of the person, or the NIP and name of the entity being granted the permission, and the type of permission (§ 4 section 2). This method requires authentication: with a Trusted Profile (Profil Zaufany) or another electronic identification means from the national node, a qualified electronic signature, a qualified electronic seal or a KSeF certificate valid for up to 2 years (§ 6 sections 1–2). Tokens generated in the previous version of the system can be used for authentication only until 31 December 2026, and they cannot be used to generate a KSeF certificate (§ 13).
The second is the paper procedure, which consists of filing a notification of granting or revoking permissions to use KSeF (ZAW-FA) with the competent head of the tax office (urząd skarbowy). This option is intended for taxpayers and entities that are not natural persons and cannot authenticate themselves with a qualified electronic seal (§ 5 section 1). ZAW-FA grants permissions to a natural person, and only one at a time – designating another person requires revoking the permissions of the previous one (§ 5 section 3). That person can then grant permissions electronically, including to an accounting office.
Granting permissions requires a precise definition of the scope of authorisation and the designation of specific authorised persons or entities. The taxpayer may change or revoke the permissions granted at any time – electronically, and in the cases under § 5 of the regulation also by filing ZAW-FA
The choice of procedure depends on the taxpayer's situation and the technical means available. The electronic procedure usually allows changes to be made in the system straight away, while the paper procedure may require longer processing by the tax authority.
Whichever procedure is chosen, it is essential to define the scope of the permissions granted precisely and clearly identify the entities that are to be authorised to act on behalf of the taxpayer. Mistakes here can cause problems with issuing invoices or unauthorised access to the system.
Permissions for accounting offices – practical solutions
The regulation on using KSeF provides two main routes for granting permissions to accounting offices when working with external accounting firms (§ 3 sections 2 and 3).
The first option is to designate the accounting office as an entity authorised to issue or access invoices on behalf of the taxpayer. In this case, invoices may be issued by natural persons designated by that office (§ 3 section 3 point 2), i.e. employees of the accounting office to whom the office has granted permissions in KSeF. If you are looking for an office to take over these duties, see our bookkeeping services.
The second option allows permissions to be granted directly to specific natural persons, including employees of the accounting office from outside the taxpayer's organisation (§ 3 section 2 point 3). This gives more control over exactly who can issue invoices on behalf of the business.
The taxpayer is completely free to choose between designating the whole accounting office as an authorised entity and granting permissions directly to specific employees of that office. Both solutions are equivalent and fully compliant with the regulation
The choice should reflect the nature of the cooperation between the business and the accounting office. In a long-term relationship with a stable accounting team, designating the whole entity may be more practical. On the other hand, when working with specific people or in situations requiring more control, granting permissions directly may be the better solution.
A business owner running a JDG (sole proprietorship) has worked with an accounting office for several years. So far, one particular accountant has issued all sales invoices based on information provided by the client. After mandatory KSeF was introduced, the business owner could choose between granting permissions to the whole accounting office or directly to that particular accountant. In the first case, any person authorised by the office will be able to issue invoices; in the second, only the designated accountant.
Managing permissions over time also matters in practice. Designating the whole entity means that the accounting office can manage its employees' permissions itself, without involving the taxpayer in every staff change. On the other hand, granting permissions directly to specific people gives the taxpayer full control over who can act on their behalf.
Granting permissions step by step
In practice, granting KSeF permissions to an accounting office requires a specific sequence of actions, depending on the chosen method of authorisation.
When granting permissions to the whole accounting office, the process goes through the following stages:
- Identifying the accounting office as an authorised entity in KSeF
- Defining the scope of permissions granted (issuing invoices, accessing invoices, or both)
- Designating the accounting office as an authorised entity in the electronic procedure (the ZAW-FA notification applies only to natural persons)
- Confirmation of the permissions by the system
- Informing the accounting office of the permissions granted
When granting permissions directly to specific employees, the procedure includes:
- Identifying the specific natural persons who are to receive permissions
- Collecting the necessary personal data of the employees concerned
- Defining the precise scope of permissions for each person
- Granting permissions through the appropriate procedure (electronic and, in the cases under § 5 of the regulation, paper)
- Confirming the permissions and informing the persons concerned
Whichever method of granting permissions is used, it is essential to define the scope of authorisation precisely and to make sure that all parties understand their obligations and permissions within KSeF
The process of granting permissions should be documented to keep the cooperation transparent and to allow changes in the future. The documentation should include information on the scope of permissions granted, the date they were granted and the procedures for using them.
Another important element of the process is agreeing how the taxpayer and the accounting office communicate about issuing invoices. You should define how the information needed to issue an invoice is passed on and how the accuracy of issued documents is checked.
Managing permissions in practice
Effective management of KSeF permissions in the relationship with an accounting office requires clear procedures and regular monitoring of compliance with them. Defining the roles and responsibilities of each party is key.
The taxpayer's obligations in managing permissions include:
- Regularly reviewing the list of persons and entities authorised to act on their behalf
- Promptly revoking the permissions of persons who have stopped working with the accounting office
- Checking that the structured invoices issued are correct
- Keeping the contact details of all authorised entities up to date
- Documenting all changes to the permissions granted
The accounting office's obligations include:
- Providing appropriate training for employees in using KSeF
- Keeping system access data secure
- Informing the taxpayer of any problems with issuing invoices
- Following the agreed communication and documentation procedures
- Regularly updating knowledge of changes in KSeF regulations
Effective management of permissions requires regular reviews of permissions and procedures for updating them. It is worth carrying out such reviews regularly, e.g. once a quarter, and whenever the team serving the taxpayer changes
Pay particular attention to situations where the cooperation with the accounting office changes. In such cases, all permissions granted must be revoked promptly and new permissions granted to the next office or employees. Delays here can cause problems with the continuity of invoicing or unauthorised access to the system.
Backup permissions also matter in practice. It is worth granting permissions to at least two people in the accounting office to ensure continuity of service if the main person responsible for issuing invoices is absent.
Benefits of using KSeF
The introduction of KSeF brings many benefits for both businesses and accounting offices, significantly improving invoicing and accounting processes.
Main benefits for businesses:
- VAT refund within 40 days – since 1 February 2026 for all taxpayers, not only those who previously used KSeF
- Invoices stored in the system for 10 years from the end of the year of issue
- Lower risk of documents being destroyed or lost
- No need to issue duplicates of invoices issued in the system
- Corrective invoices "in minus" settled in the period in which they are issued
- Fewer formalities with the tax authorities
- No obligation to send JPK_FA files at the authorities' request for invoices in KSeF (Article 193a § 1a of the Tax Ordinance Act (Ordynacja podatkowa))
Benefits for accounting offices:
- Standardised invoicing according to a single template
- A clear moment when the counterparty receives the invoice (the day the KSeF number is assigned)
- More efficient posting thanks to the XML structure
- Fewer errors caused by different invoice formats
- The possibility of automating accounting processes
- More secure document storage
KSeF reduces traditional e-invoicing problems such as different formats, delivery issues and the need to enter data into accounting systems manually. The structured XML format allows data to be processed automatically
More efficient posting is particularly important for accounting offices. Structured invoices contain data in a standard XML format, so they can be imported automatically into accounting systems without retyping information by hand. This significantly reduces the risk of errors and the time needed to process documents.
The system also makes invoicing fully transparent. All parties to a transaction have access to the same information about the status of an invoice, its delivery and any corrections. This reduces the typical communication problems associated with traditional invoicing.
Before KSeF was introduced, an accounting office serving 50 clients had to deal with invoices in different formats – paper, PDF and various electronic systems. After switching to KSeF, invoices covered by the system have a uniform structure, which made it possible to automate a significant part of posting and shorten document processing time.
Security and archiving in KSeF
KSeF was designed with security requirements and long-term document archiving in mind. The system is intended to protect data and keep it available for the storage period set out in the VAT Act.
Main security features of the system:
- Encryption of all data transmissions between users and the system
- Multi-level authentication of access to system functions
- Regular backups of all stored documents
- Access monitoring and detection of attempts at unauthorised use
- Compliance with European personal data protection standards (GDPR)
- Security certification in line with public administration requirements
The system stores structured invoices for 10 years from the end of the year in which they were issued (Article 112aa section 1 of the VAT Act). During this time, the taxpayer does not have to store them separately, and if the limitation period for the tax liability ends later, the taxpayer stores them outside KSeF until it expires (Article 112aa section 2). This period is usually longer than the limitation period, which as a rule is 5 years from the end of the year in which the tax payment deadline passed (Article 70 § 1 of the Tax Ordinance Act), which helps in the event of tax audits or commercial disputes.
Invoices stored in KSeF are protected against accidental loss or damage on the taxpayer's side. The content of an invoice that has been assigned a KSeF number is not changed – errors are corrected with a corrective invoice
Access to archived documents is particularly important for accounting offices. The system provides access to clients' invoices for as long as the office holds the appropriate permissions. Access does not expire automatically when the cooperation ends – the taxpayer should then revoke the office's permissions.
In addition, each invoice has a unique KSeF number and the date it was assigned, which makes it easier to clear up doubts during audits or disputes.
Integration with accounting systems
One of the key advantages of KSeF is that it can be integrated with the various accounting systems used by accounting offices. This significantly improves accounting processes and reduces the risk of errors caused by manual data entry.
Ways of integrating with accounting systems:
- Direct integration via API (application programming interface)
- Import/export of XML files
- Use of dedicated integration modules
- Real-time data synchronisation
- Automatic posting of sales and purchase invoices
Many accounting systems offer ready-made KSeF integration modules. Accounting offices should consult their software providers about the integration options available and updates to the current version of the system and the FA(3) structure.
Integrating accounting systems with KSeF makes it possible to download purchase invoices from suppliers automatically and to post sales invoices issued in the system automatically. This significantly reduces the workload involved in bookkeeping
The ability to download purchase invoices from suppliers automatically is particularly important. When a supplier issues an invoice in KSeF, the buyer's accounting software integrated with KSeF can download it and then post it according to the agreed posting rules.
This reduces the traditional problems of late delivery of invoices, lost invoices or the need to enter data manually. For accounting offices, this means much more efficient processes and the ability to serve more clients without a proportional increase in staff.
