Qualified Electronic Seal for KSeF: Your Digital Key to the National e-Invoicing System

In the world of digital administration, where every second of the business process counts, traditional authorization methods are no longer sufficient. This article explains why a qualified electronic signature is not enough for large organizations and why the qualified electronic seal for KSeF is becoming the new standard for security and Business Continuity. You will learn how to effectively manage your company's identity within the Ministry of Finance's system and avoid decision-making paralysis.

For decades, the classic, ink-soaked company stamp symbolized a document's validity. However, in the digital reality imposed by the National e-Invoicing System (KSeF), a physical stamp has no legal effect. KSeF is, in practice, a powerful, central database of the Ministry of Finance, to which your invoices must be sent in real-time.

For this system to "let you in," it must be absolutely certain of the identity of the entity sending the data. This is where the biggest challenge for multi-company structures arises: how do you prove that "we are who we are" without paralyzing the board's work?

Most organizations make a common mistake at the start by equating system authentication with an action that must be performed by a human. Until now, the taxpayer usually relied on the electronic signature (often the qualified electronic signature of the CEO). However, a signature is inextricably linked to a specific natural person—it contains their name, surname, and PESEL number.

In the context of process automation in a large company, such a solution is a bottleneck. The qualified electronic seal is a completely different category. It is the digital identifier of your company. Its structure does not contain the name of John Smith, but the NIP number (Tax Identification Number) which is key to the business.

For an entrepreneur managing an extensive structure, the electronic seal for KSeF is not another technological gadget but the foundation of independence. It enables authentication in KSeF at the organization level, not the individual level. As a result, when using the taxpayer application or integrating ERP systems, you log in as a company.

Crucially, thanks to the e-seal, you do not have to submit the ZAW-FA (a notification of granting authorizations) because you immediately and automatically gain access to the system under ownership rights. The qualified seal is your "Master Key" that opens the door to e-invoicing without involving the private data of board members or the chief accountant.

What is the legal difference between a qualified electronic signature and an electronic seal?

Many managers and financial directors use the terms signature and seal interchangeably, which can lead to costly misunderstandings in the context of KSeF. From a legal standpoint, the difference is fundamental and concerns the entity that the instrument represents.

The qualified electronic signature is the digital equivalent of a handwritten signature. It is always, without exception, assigned to a natural person. This means that the signature certificate contains the data of a specific individual, most often their PESEL number. Using such a signature in the system is a message: "Approved by John Smith."

Conversely, the qualified electronic seal is a solution dedicated to a taxpayer that is not a natural person. You could say it is your company's identity card in the virtual world.

Inside this digital seal, you will not find the name and surname of the CEO or authorized signatory. The key identifier is the company's NIP number and its name. The e-seal is used to ensure the authenticity of the origin and integrity of the data, but on behalf of the entire organization, not a single employee.

Why is this distinction so important for large entities? Because basing mass processes (such as sending thousands of invoices) on a specific person's electronic signature is risky. If the CEO is absent, organizational changes are underway, the signature is revoked, or the person simply leaves the company, the entire process comes to a halt.

The qualified seal is more durable—it is tied to the company, which usually lasts longer than the tenure of a management board. This makes the electronic seal for KSeF the only logical choice for entities looking to build stable and scalable accounting processes.

Why is the qualified seal the foundation of KSeF authentication for large entities?

In the National e-Invoicing System ecosystem, the first login is a critical moment. It defines the so-called primary ownership rights. If an entity logs in using the qualified electronic signature of a board member, the system recognizes a natural person acting on the company's behalf.

This is permissible but, on a corporate scale, it is extremely inefficient. It requires that specific person to be "connected" to the system every time new permissions need to be granted or a session needs to be re-authorized.

The use of a qualified electronic seal changes the rules of the game. Using it for authentication in KSeF makes the system see: "Okay, the COMPANY has logged in." The seal gives you ownership status independent of personal details. This is especially important in multi-company organizations where management boards change and structures evolve.

Possessing the "Master Key" in the form of a seal means that KSeF can be used continuously. Financial systems can connect to the Ministry of Finance (MF) cloud automatically, identifying themselves with the seal, not a token plugged into the CEO's laptop.

Moreover, this approach drastically simplifies authorization management. Instead of cascading permissions from the CEO to the CFO, and then to the accountants (which creates a long chain of dependence), a company authenticated by an electronic seal can grant permissions directly to employees or systems.

The qualified seal becomes the central point of trust. Without this foundation, the entire invoicing process in a large company hangs by a thread—namely, the private signature and availability of a single management board member. In modern business, this is an unnecessary operational risk.

How can a foreign entrepreneur use KSeF without a Polish PESEL number?

The ownership structure of many companies operating in Poland includes foreign holding entities or management boards composed of foreign nationals. Here, a classic administrative barrier arises: for years, Polish state systems have been structured around the PESEL number.

For a foreign entrepreneur who does not have this number, attempting to log in to systems like the National e-Invoicing System using a traditional qualified signature (issued in another EU country) can be an arduous process. This often involves problems with Polish gateways recognizing foreign identifiers.

The qualified electronic seal completely eliminates this issue. Because the seal is based on the NIP number of the Polish company, the nationality or possession of a PESEL number by board members ceases to be relevant. The KSeF system does not verify the identity of the natural person (e.g., a CEO from Germany or the USA) but the identity of the legal entity, which is registered in Poland and has an active NIP.

For international corporations, this is a game-changer solution. Thanks to the qualified electronic seal, foreign management does not have to go through complicated procedures to obtain Polish identification numbers just for the company to issue an invoice.

The seal works across borders, representing the company's interests in a fully automated manner and in accordance with Polish law. This means that the barrier to entry into the world of digital settlements for entities with foreign capital simply disappears.

Is your company ready for mandatory KSeF? Bottlenecks vs. Business Continuity

Let's talk about real-life scenarios that keep financial directors up at night. The classic situation in many companies is as follows: the end of the month is approaching, the accounting department has prepared a batch of thousands of documents, and the invoice for a key project must be sent to the system to maintain cash flow.

In the world before KSeF, sending a PDF file by email was simple. In a reality where mandatory KSeF is a fact, the document must be authenticated before the Ministry's gateway will even accept it. And here lies the problem: the only person with the technical authority to authorize the shipment—usually the CEO—is offline. On vacation, in a different time zone, no signal on a plane.

The result? The invoicing process stops. In modern business, especially in multi-company structures, we cannot afford such a dependence on the physical availability of one person. This is a bottleneck that, in extreme cases, can cost the company the loss of a contract or contractual penalties. The electronic seal for KSeF removes this human factor from the critical equation. Thanks to it, the authentication process becomes independent of the management board members' calendars.

KSeF implementations based on the seal allow for full automation. The e-seal, especially one integrated directly with your financial or ERP system, works in the background. The system can issue invoices at night, on weekends, or on holidays, without the need for the management board to manually "click."

A machine (ERP) communicates with a machine (KSeF), using the company's digital identity. This is the definition of Business Continuity—a guarantee that the company operates smoothly, regardless of the physical location of its decision-makers.

Team data security: Does the accounting employee have to use their e-signature?

Another aspect often overlooked during the implementation of invoicing systems is the comfort and legal security of employees in the financial and accounting departments. In smaller companies, it sometimes happens that the accountant uses their own profile or electronic signature to send documents.

On a corporate scale, this practice is unacceptable and risky. Why? Because an electronic signature contains personal data. Forcing employees to countersign the company's sales invoices with their own name, surname, and PESEL number compromises their privacy and unnecessarily burdens them with responsibility that should rest with the business entity.

The use of an e-seal resolves this ethical and legal dilemma. Thanks to it, you do not force accounting employees to expose themselves. In the National e-Invoicing System, the issuer listed is the entity—i.e., the company with its NIP number, not "Mrs. Anna from Accounting." When performing their duties, employees use the permissions granted to them to use the corporate seal or initiate a process that is automatically sealed in the background.

This approach builds team data security. The organization's action is visible in the system logs and on the Official Receipt Confirmation (UPO). This provides great comfort for employees who know they are acting on behalf of the company and that their private digital identity is not "attached" to every trade document.

In the era of GDPR and growing digital awareness, the qualified seal is therefore a tool that professionalizes the employer-employee relationship in the context of handling accounting processes.

The end of the pendrive era: Why are physical certificates and cryptographic cards obsolete?

For years, a qualified certificate was associated with a physical device: a cryptographic card inserted into a reader or a USB token resembling a pendrive. While this is acceptable for signing individual contracts once in a while, in mass processes, such as handling e-invoices, this technology is archaic and inefficient.

Imagine the situation in a large company: should someone run around the office with a token plugged into a laptop, passing it from hand to hand? Or worse—leave it permanently plugged into a server, which is a gross violation of security principles? Physical media get lost, they break down, and their drivers often cause technical problems.

At Autenti, and in the modern approach to trust services, we have opted for a cloud-based (Cloud-Native) solution. The qualified electronic seal for KSeF in this model does not require any physical hardware at the client's end. Your "digital stamp"—i.e., the cryptographic keys—is securely stored on certified HSM (Hardware Security Module) servers of a trust service provider, such as Autenti or in partnership with entities like KIR or Eurocert (depending on the certificate provider).

What does this mean for the entrepreneur in practice? Availability and scalability. All that is needed is a network connection for the ERP system to invoke the seal via a secure API. Traditional methods involve manual work—document by document. The electronic seal in the cloud enables mass processing. We can authorize hundreds, even thousands of documents in a few seconds.

Furthermore, a cloud certificate will never be lost, physically stolen from a desk, and its use can be strictly monitored and logged. This is technology prepared for the era of Big Data and automation, where a physical token is simply unnecessary ballast.

Automation and ERP: What does mass invoicing in KSeF look like technically?

Can you imagine manually signing 10,000 invoices per month? In the era of mandatory KSeF, this is a real risk of paralysis if you choose the wrong tools. In large organizations, invoices are sent in batches, often at night, thousands per minute. This is a classic Machine-to-Machine (M2M) process.

Inserting a human with a cryptographic card (qualified signature) into this process is asking for trouble:

• The necessity of physically entering a PIN—blocks automation.
• Session blocking—security systems often disconnect the connection when there are too many requests from one token.
• Human errors—fatigue or a mistake in choosing the certificate.

Therefore, for KSeF on a large scale, you do not use a "signature," but a fully automated solution. The qualified electronic seal, securely installed on a server (HSM) or available as a cloud service, automatically "stamps" the XML files and sends them to the Ministry of Finance.

Thanks to the integration of the ERP with the cloud seal via API, the process works 24/7, without vacations or coffee breaks. The financial system generates a batch of structured invoices, sends them through a secure channel to the sealing service (e.g., Autenti), and there, the documents gain legal force in a fraction of a second.

This is the only guarantee of document integrity and invoicing continuity in a holding model. For the IT director, it means an end to driver issues, and for the management board, the certainty that the digital equivalent of the document in KSeF is always accurate.

Do you need to submit ZAW-FA? With the seal, you gain automatic access

Many entrepreneurs associate the start in KSeF with the necessity of submitting the ZAW-FA notification form to the Tax Office. In the standard path (without the seal), this is indeed necessary to report a specific person (e.g., the CEO) as authorized to manage the system. Unfortunately, this path can be bumpy: the form must be processed by an official, which means waiting for acceptance. In business, "time is money," and waiting for authorization blocks implementation.

Possessing a qualified electronic seal completely changes this scenario. It is a kind of "fast track." Because the seal contains the company's NIP number, the KSeF system recognizes the entity's identity automatically at the moment of first use. You do not have to send any letters to the Tax Office or wait for their acceptance.

Thanks to the seal, the primary ownership rights are generated instantly. This means that immediately after purchasing and installing the seal, you can log in, authorize your ERP systems, and start invoicing. ZAW-FA becomes a procedure needed only in specific emergency cases (e.g., when it is impossible to authenticate with the seal), but in a modern, automated company, the seal is the key that opens the door to the system without unnecessary bureaucracy.

KSeF implementation in multi-company structures – how to manage authorizations and the e-seal?

Holding organizations, capital groups, or Shared Service Centers (SSCs) face the challenge of scale. Having several special-purpose companies means the necessity of managing documentation and access for each of them separately. In the traditional model, this would require an army of proxies and hundreds of UPL-1 forms. In the digital model, based on the qualified e-seal, this process becomes transparent and centralized.

By implementing the seal in the cloud model for multiple entities, you can grant permissions in a cascading, but controlled manner. Each company in the group has its own seal (with its own NIP and entity name), but technically, they can be served by one integration platform. Thanks to this, authorization management becomes simpler: the system administrator can define which ERP system or which accounting team has the right to invoke the seal for a specific company.

This ensures not only compliance but also a high level of corporate data security. In the event of employee turnover, you do not have to revoke certificates at the Ministry (which would be necessary if the employee used their own signature). It is enough to revoke access to the sealing platform within the company. Implementations based on the seal allow you to maintain order in company documents and the structure of permissions, which is an invaluable asset during audits and tax inspections.

When will KSeF become mandatory? Key dates (2025 and 2026) for your business

The KSeF implementation schedule has been finally crystallized. The time for guesswork is over—we have concrete dates and financial thresholds that determine the moment of entry into the mandatory system. For large, multi-company organizations, it is crucial to precisely determine which group the individual entities within the capital group fall into.

The mandatory KSeF calendar has been divided into three stages, depending on the scale of the business:

• February 1, 2026 – this is the "zero" date for the biggest players on the market. The obligation will cover entrepreneurs whose sales value (including the tax amount) exceeded PLN 200 million in 2024. If your company generates such turnover, you have no time to lose—the system must be ready at the beginning of the year.
• April 1, 2026 – just two months later, the system will become universal. From this date, KSeF will be mandatory for all remaining entrepreneurs (active VAT taxpayers), regardless of whether they reached the PLN 200 million threshold.
• January 1, 2027 – the legislator has provided a transitional period only for the smallest entities whose scale of operation is minimal (turnover up to PLN 10 thousand per month). For them, digitalization will become a requirement only in 2027.

What does this mean for financial and IT directors? 2025 is the final stretch. Although the formal obligation starts in 2026, large-scale implementation processes take months. You should check your 2024 turnover to know whether you fall into the February or April deadline and not wait until the last moment to obtain a qualified electronic seal for KSeF, as this is a huge operational risk.

Why is ZAW-FA not enough? The role of the seal in ERP integration and token generation

Many decision-makers fall into the trap of thinking that granting administrative rights (ZAW-FA) to a specific person is enough for the company to be "KSeF ready." This is a mistake that comes to light at the first attempt to connect the software. We must clearly distinguish between two things: access for a person (logging in via the portal) and access for a machine (API integration).

ERP class programs—such as SAP, Oracle, Microsoft Dynamics, Comarch ERP, or Enova—do not "log in" to KSeF using a login and password. They communicate only through an authorization token (a technical certificate). And here is the crux of the matter: without a valid electronic seal, you cannot generate this token.

The seal is necessary at three critical technical moments:

1. Generating the token for the system: Only authentication with the seal (as the owner of the company's digital identity) allows you to generate the string of characters that is entered in the accounting system settings. ZAW-FA does not enable this.
2. Renewing authorizations: Tokens and certificates have a validity period (usually 2 years). Their renewal requires the re-use of the seal. The lack of a seal at this moment means the sudden disconnection of the ERP system from the Ministry of Finance.
3. Emergency mode (offline): KSeF provides for the possibility of issuing invoices offline in case of failure, but this option is only available to entities that have an ** active seal and certificate**.

To organize the knowledge, we have prepared a comparison of the differences that should be shown to the IT and Compliance departments:

Summary – what should you remember?

The transformation from the traditional signature to the seal is not just a technological requirement; it is a strategic decision. Here are the most important conclusions:

• The Seal is the Company's Identity: Unlike the signature (natural person), the seal represents the organization (NIP). It is your "Master Key" to KSeF.
• Business Continuity: You make the invoicing process independent of the CEO's presence, vacations, or mood. The e-seal allows systems to operate automatically 24/7.
• Solving Foreign Issues: The lack of a PESEL number for board members is no longer a barrier. The qualified seal is based on the company's data, not the manager's nationality.
• Employee Security: Accounting does not have to sign invoices with a private name. The electronic seal protects the team's personal data.
• Cloud Trumps Token: For large volumes and automation, a Cloud-Native solution and API integration are the only path to efficiency. Physical cards are a thing of the past.

Where to buy an electronic seal for KSeF?

If you are looking for a proven, cloud-based solution that can handle mass document sending and API integration, you can purchase such a seal at Autenti.

Secure your company's processes now. Contact us to receive a dedicated offer:

• Submit a price inquiry via the form on our website.
• Or write directly to: sales@autenti.com