Briefing document & Podcast: Poland E-Invoicing, E-Reporting and KSeF Mandate

• E-Invoicing refers to the electronic issuance and exchange of invoices in a structured format through a central platform. In Poland, this means using the Krajowy System e-Faktur (KSeF) to issue invoices that are digitally authenticated and delivered to the buyer via the government’s system. The e-invoice is the legal invoice, and paper/PDF invoices (outside a few exceptions) will no longer be valid once the mandate kicks in. [dudkowiak.com]
• E-Reporting refers to the electronic submission of transaction data to tax authorities. This ensures authorities receive information (like invoice details) for VAT monitoring. In Poland’s model, KSeF effectively combines e-invoicing with real-time e-reporting: when an invoice is issued through KSeF, the tax authority automatically receives all the data instantly. For transactions not covered by KSeF (e.g. some consumer sales or invoices from foreign suppliers), reporting will still be done via periodic VAT returns or existing SAF-T files. [dudkowiak.com], [dudkowiak.com]

Timeline of Implementation: Past, Current, and Future

• January 2022 – Voluntary KSeF Launch: The KSeF platform became available for voluntary use. Businesses could issue structured e-invoices through KSeF (in FA(1) or FA(2) format at that time) alongside traditional invoices. This pilot phase was designed to familiarize taxpayers with the system before it became obligatory. [polishtax.com]
• EU Authorization in 2022: In order to mandate e-invoicing, Poland obtained a special derogation from EU VAT rules. The Council Implementing Decision (EU) 2022/1003 (granted in June 2022) authorized Poland to require electronic invoices without individual buyer consent. This legal green light was necessary since EU law normally requires acceptance of electronic invoices by the recipient; the derogation allows Poland to make e-invoicing the default for all transactions. [ec.europa.eu]
• Initial Plan for 2024: Following EU approval, Poland’s Parliament initially amended the VAT Act on 16 June 2023 to set 1 July 2024 as the start of mandatory e-invoicing. The plan was to require all B2B invoices to be issued via KSeF from that date, with minor exceptions. However, this aggressive timeline was reconsidered due to technical and business readiness concerns. [ec.europa.eu]
• Mid-2023 – Postponement Decision: In response to feedback during consultations, the Ministry of Finance announced a postponement. The rollout was pushed to 2026, giving an extra 18 months for preparation. The formal delay was enacted by a law passed on 9 May 2024, which revised the go-live dates. [ec.europa.eu]
• August 2025 – Final Law with Phased Rollout: On 27 August 2025, the Polish President signed the Act (of 5 August 2025) introducing mandatory e-invoicing with a phased implementation in 2026–2027. This law (which amends the VAT Act of 2004) is the definitive mandate: [kpmg.com]
  • Phase 1 – from 1 February 2026: Large taxpayers must comply. “Large” means those whose 2024 turnover (gross sales) exceeded PLN 200 million. These businesses must start issuing all invoices via KSeF from February 1, 2026. [kpmg.com]
  • Phase 2 – from 1 April 2026: All other VAT-registered businesses in Poland must start e-invoicing via KSeF. This brings in medium-sized, small, and most micro businesses. Essentially, any company that wasn’t mandated in Feb 2026 is covered by April 2026, except the very smallest as noted below. [kpmg.com]
  • Phase 3 – from 1 January 2027: Micro-entrepreneurs and exempted small firms must comply. A temporary exemption covers businesses with monthly sales up to PLN 10,000 (approximately €2,150) until end of 2026, recognizing that these are often sole proprietors or very small entities. Starting 2027, they too must use KSeF. By this date, the mandate will be universal – all invoices issued by Polish taxpayers (with only narrow exceptions) will go through the KSeF system. [kpmg.com]
• Transition Period in 2026: The Polish authorities have designated 2026 as a transition/grace period. Even though e-invoicing becomes obligatory in 2026 (per the phases above), no financial penalties will be imposed for non-compliance until 1 January 2027. This gives businesses leeway to iron out issues. Additionally, during 2026 some existing invoice practices can continue in parallel: [crowe.com]
  • Businesses may still issue cash-register receipts and simplified invoices (for transactions up to PLN 450) in the old way until end of 2026. [crowe.com]
  • If technical problems occur, invoices can be issued temporarily outside KSeF (see “Offline mode” below) without penalty, as long as they are reported later.
  • Essentially, 2026 is treated as a year of “enforcement light” – the system is mandatory by law, but sanctions only kick in after a grace period.

Scope of Transactions Covered by the Mandate

• Domestic B2B Transactions: All business-to-business sales within Poland must be invoiced via KSeF. This includes any supply of goods or services where both the supplier and customer are registered for VAT in Poland (even if one or both are VAT-exempt entities). Such invoices, once the mandate is in effect, have to be in the structured electronic format and submitted to KSeF – paper or PDF invoices will no longer satisfy legal requirements. For instance, if a Polish company sells to another Polish company, the invoice must be issued through KSeF, which will then make it available to the buyer. The buyer is expected to retrieve the invoice from KSeF (most will do so via software integration). In short, domestic B2B invoices = KSeF invoices. [dudkowiak.com]
• B2G (Business-to-Government) Transactions: Invoices issued to public sector entities (government departments, municipalities, public hospitals, etc.) must also go through KSeF. In fact, Poland already required public bodies to accept e-invoices (via a platform called PEF using the EU standard) since 2019. KSeF will integrate with or replace that, making the process uniform. If a business is billing a Polish government agency, from 2026 that invoice must be in KSeF (formatted to EN 16931 standard). Public entities will then receive it through the system. (They may continue to use the PEF/Peppol infrastructure internally, but suppliers won’t need to worry about that – submitting to KSeF suffices.) [ec.europa.eu]
• Cross-Border Outbound Invoices (Exports and Intra-EU sales): If a Polish company sells to a business abroad (whether an EU customer or a non-EU customer), the invoice must be issued via KSeF as well. In other words, Polish VAT-registered suppliers must report their foreign sales in KSeF, even if those transactions are zero-rated (0% VAT) such as an intra-Community supply or an export. However, the foreign buyer will not retrieve the invoice from KSeF (since only Polish taxpayers have access); instead, the Polish seller must deliver a copy of the invoice to the foreign trading partner through other means (for example, sending a PDF by email or via a commercial e-invoicing network). To facilitate this, KSeF provides a QR code and unique ID for each invoice. The Polish seller is obliged to include that QR code on the invoice copy sent to the foreign customer. This allows the foreign buyer or tax authorities abroad to verify the invoice’s authenticity on the Polish system if needed. The key point is: Polish companies must put export and intra-EU invoices into KSeF (for Polish reporting purposes) and also send the invoice to the buyer in the buyer’s country (for the buyer’s accounting purposes). [sovos.com] [poland-accounting.eu], [sovos.com] [poland-accounting.eu]
  • Example: A Polish manufacturer sells goods to a German business. The Polish company issues the invoice through KSeF (marking it as an intra-Community supply). KSeF clears it and returns a QR code/ID. The Polish company then sends a PDF or printout of the invoice (including that QR code) to the German customer. The German customer treats the PDF as the invoice for bookkeeping, and the Polish authorities already have the invoice data via KSeF.
• Cross-Border Inbound Invoices (Imports and foreign supplier invoices): If a foreign company (not registered in Poland) issues an invoice to a Polish business (for example, a French supplier selling goods to Poland, where the French company isn’t in Poland’s VAT system), that invoice will not go through KSeF. The foreign supplier will issue the invoice according to their own country’s rules (or any agreements with the Polish buyer). The Polish buyer will receive it (likely as PDF/paper) outside KSeF and will handle Polish VAT reporting on it via the normal reverse-charge or import VAT process. KSeF does not currently allow foreign-supplied invoices to be “uploaded” by Polish recipients, and foreign companies without a Polish VAT ID can’t access KSeF. Thus, these invoices remain outside the real-time reporting system. Polish tax authorities will learn about them through the buyer’s VAT return and associated SAF-T file (JPK_V7M) as they do today. Importantly, if a foreign company is registered in Poland for VAT (even without an establishment), see the next section on taxable persons – those invoices might fall under KSeF. But purely foreign-to-Poland transactions with no Polish VAT registration on the supplier side are out of scope. [ec.europa.eu]
• Domestic B2C Transactions: Business-to-consumer invoices are excluded from mandatory e-invoicing. If a business sells to a private individual (who is not VAT-registered), they are not required to issue the invoice via KSeF. In practice, most B2C sales in Poland are done via cash registers that produce receipts. Those receipts (or simplified invoices) will continue to be used. If a consumer asks for an invoice, the seller can issue them a paper or PDF invoice as today. The Polish Ministry of Finance explicitly stated that consumer invoices will not be covered by KSeF. That said, KSeF will allow voluntary B2C invoices: a business may send an invoice through KSeF to a consumer if, for example, they want to have it recorded centrally (and the consumer is given a way to access it via a verification code). But this is optional. So a web shop selling to individual customers can continue emailing PDFs (or providing receipts) and does not need to KSeF-report each sale. The rationale is that private consumers do not have the ability to log into KSeF to fetch invoices, so a mandate there wouldn’t work well. Summary: B2C remains largely outside KSeF, aside from optional use. [gov.pl], [ec.europa.eu] [gov.pl] [sovos.com]
• Other Exclusions and Special Cases: A few situations are carved out or have special handling:
  • Small businesses under the threshold: As noted, those with very low sales (≤ PLN 10k per month) are exempt until 2027. Also, during 2026, cash register invoices and simplified invoices can be issued as usual (the law allowed those to continue outside KSeF until end of 2026). This eases the transition for small retailers. [kpmg.com], [dudkowiak.com] [crowe.com]
  • “Digitally excluded” entities: The law makes an allowance that if a taxpayer cannot use the electronic system due to lack of internet access (a rare scenario), there may be an exemption pathway. In practice this is narrowly interpreted – almost all businesses are expected to use KSeF, but the Ministry can issue an exemption in specific hardship cases (to be defined by regulation).
  • Self-billing and OSS/IOSS: If a customer issues the invoice on behalf of a Polish supplier (self-billing) and that customer is not in Poland’s system, it’s tricky – current guidance suggests such invoices might be handled outside KSeF and then reported via summary. Also, transactions declared via special schemes like OSS/IOSS (one-stop-shop for EU digital services, etc.) are excluded from KSeF because they are reported in separate systems. [gov.pl]
  • Certain documents: pro forma invoices, corrective notes (which will be eliminated entirely), margin scheme invoices, etc., have specific treatments. For example, tickets that serve as invoices (e.g. toll road tickets, transport tickets) are excluded from KSeF. Also, invoices under the VAT RR scheme (used for farmers) will be allowed into KSeF only from 2026 (optional) and mandated later, since that required an update to the schema. These nuances aside, the rule of thumb is that standard sales and purchase invoices in the scope of Polish VAT must be in KSeF. [gov.pl] [sovos.com]

• B2B and B2G invoices with Polish VAT – Yes, via KSeF.
• Invoices for cross-border sales issued by Polish entities – Yes, via KSeF (with external delivery to buyer). [poland-accounting.eu], [sovos.com]
• Invoices from foreign entities not in Poland – No, remain outside KSeF.
• B2C invoices and receipts – No mandate, handled as today (though voluntary use of KSeF is possible). [gov.pl], [sovos.com]

Taxable Persons in Scope: Established vs. Non-Established

• Polish-Established Businesses: Any business with a registered office in Poland (domestic company) is definitely in scope. This includes companies and individuals conducting business in Poland, regardless of size or VAT status (even VAT-exempt businesses issuing invoices must use KSeF). The KPMG summary of the law highlights that “all taxpayers, both those active and exempt from VAT, must issue electronic invoices” via KSeF. So if you’re a Polish business, you will be using KSeF by 2026 (or 2027 for micro). This covers all Polish legal entities, partnerships, sole traders, etc., who are VAT-registered. [sovos.com] [kpmg.com]
• Foreign Businesses with a Fixed Establishment in Poland: A “fixed establishment” (FE) is a stable presence in Poland of a foreign company, through which it makes supplies. The mandate applies to foreign entities that have a fixed establishment in Poland and that establishment is involved in the transactions. For example, if a German company has a branch or logistics hub in Poland (and that constitutes an FE for VAT purposes), and it sells goods from that Polish hub, it must issue invoices via KSeF for those sales. The Polish VAT law (after amendment) states the e-invoicing obligation covers taxpayers with a Polish registered office or permanent establishment in Poland that is used for the supplies in question. In practice, foreign companies with FE will have a Polish tax ID (NIP) and will use KSeF just like a Polish company. Many global firms operating in Poland fall in this category. [sovos.com]
• Foreign Businesses VAT-Registered in Poland (No Establishment): This is a nuanced case. Some companies are registered for Polish VAT but have no fixed establishment – for instance, a company that occasionally sells or organizes events in Poland, or an e-commerce seller registered under distance selling rules (before OSS), etc. According to guidance, having a Polish VAT registration alone does not automatically trigger the KSeF mandate if the company has no establishment in Poland. The law’s wording means that if a foreign entity is merely VAT-registered (perhaps via a fiscal representative) but does not have a physical presence or personnel in Poland, it might be exempt from mandatory e-invoicing. In other words, Poland is not forcing those foreign businesses to obtain KSeF credentials and issue invoices through KSeF for their Poland-related sales – since administration could be too complex. For example, if a US company without Polish establishment sells goods in Poland and is VAT-registered just to account for Polish VAT, it may issue invoices as it does normally and just file VAT returns as required, rather than through KSeF. This interpretation aligns with the idea that KSeF covers “businesses with a registered office or fixed establishment in Poland”, and explicitly “foreign businesses not subject to VAT in Poland are exempt”. Here “not subject to VAT” effectively means not registered or not having to charge Polish VAT. So, a foreign company only selling under reverse-charge in Poland (with no Polish VAT to charge) wouldn’t use KSeF either. [sovos.com] [ec.europa.eu]
  • It’s worth noting, however, that many foreign businesses choose to appoint a Polish fiscal representative or establish a branch when doing frequent business in Poland. Those that do will likely end up in scope. The Polish Ministry of Finance is aware of the EU’s upcoming “VAT in the Digital Age” (ViDA) proposals, which may require cross-border e-invoicing within the EU by 2028–2030. So Poland is focusing KSeF now on domestic transactions and Polish entities, while preparing for possible expansion when EU rules harmonize cross-border e-invoicing. [ec.europa.eu]
• Entities Not in Scope: If a company is completely outside the Polish VAT system (no Polish VAT number, no fixed establishment), it has no obligations under KSeF. Similarly, purely private persons (non-business) who occasionally sell something (not in business context) and public bodies for their non-business activities are not in scope. Also, as mentioned, the smallest micro-businesses got an extension to 2027 before they must comply. During 2026, if they choose not to use KSeF yet, that’s permitted. [ec.europa.eu] [kpmg.com]
• Buyers vs. Sellers: The obligation primarily falls on issuers of invoices. A business that is mandated to use KSeF must issue all its outbound invoices through the system. What about receiving invoices? All Polish VAT payers will be on the receiving end of KSeF invoices once their suppliers start using it. For example, in February 2026, a medium-sized company that isn’t mandated until April 2026 will still begin receiving some invoices via KSeF (from their large suppliers). They need to be ready to fetch those invoices. The law effectively requires buyers to accept invoices via KSeF – since a valid invoice will be in KSeF, the buyer cannot demand a paper version instead. So even before a company’s own mandate date, it might need to access KSeF to get incoming invoices. [polishtax.com]

Data and Format Requirements (E-Invoice Content)

• Structured Format – XML Schema FA(3): Poland uses a structured XML format for e-invoices. The current version for mandatory e-invoicing is often called “FA(3)” (Faktura 3) – the third iteration of the schema. This schema is based on the EU standard EN 16931 for electronic invoicing and its related Peppol BIS 3.0 format. In fact, the KSeF system is designed to be compatible with the Peppol framework, meaning it follows the same core data model. The FA(3) schema defines all the required fields and structure that an invoice must have for KSeF. Every invoice submitted must be valid against this schema or the system will reject it. The format is essentially a standardized XML file containing all invoice details. [dudkowiak.com] [polishtax.com]
• Mandatory Content: The e-invoice must contain all information required by the Polish VAT Act (which is similar to what’s required on paper invoices by law) – for example:
  • Supplier and buyer details (names, addresses, and Tax Identification Numbers like NIP for Polish entities or EU VAT ID for foreign buyers). [poland-accounting.eu]
  • Invoice number (assigned by the supplier’s system, unique sequential number).
  • Invoice date and supply date.
  • Line items with description of goods or services, quantity, unit price, net amount.
  • VAT rates applied, split of net amounts per rate, and VAT amount per rate.
  • Total net, total VAT, and gross total.
  • Currency and exchange rate if not in PLN.
  • Payment terms, method, bank account (especially for split payment mechanism compliance).
  • Any required annotations (like “reverse charge” or special scheme indicators, if applicable).
  • Specific tags indicating transaction type if needed (for example, an indicator if this is an intra-EU supply or an export, so that VAT = 0 but transaction is reported).
  Essentially, anything that a paper invoice needed to show must be captured in structured fields. There are also additional fields that are purely for reporting: e.g., an indicator if an invoice is a correction (credit note) or an advance invoice, etc., which helps the system process it correctly.
• KSeF Unique ID and QR Code: When KSeF accepts an invoice, it will assign a unique identifier (KSeF ID) and apply a time stamp. The system can generate a QR code that encodes a link or identification for the invoice in the KSeF database. If the invoice is delivered to a buyer outside the system (like a foreign buyer or consumer), this QR code must be included on the document. The QR code allows verification of the invoice’s authenticity and details via KSeF. It’s effectively a way to tie an external document back to the official record in KSeF. [polishtax.com] [poland-accounting.eu]
• Attachments: The system can also handle certain structured attachments. You cannot attach just any PDF or image to a KSeF invoice for transmission – since one goal is to eliminate unstructured data. However, a limited range of file attachments (like certain standardized annexes) may be permitted (for example, a XML with additional details). In general, though, anything necessary for the invoice should be in the invoice XML itself.
• Language and Currency: Invoices can be issued in any currency (with PLN conversion for VAT if needed) and any language. Many companies will likely issue bilingual invoices (Polish-English) in the structured data if dealing with foreign partners. The schema supports multi-language content. The key is, regardless of language, the data fields are fixed and standardized.
• Digital Signature (not required): In the KSeF system, invoices do not need a traditional digital signature from the supplier to be considered authentic, because submission via an authorized channel itself ensures authenticity. KSeF will digitally sign or seal the invoice when accepted (or at least record it with a time stamp). This is a shift from past practice where sometimes e-invoices needed to be signed or sent via EDI with agreement – with KSeF, the legal authenticity and integrity is guaranteed by the system. So, companies do not have to sign each invoice with an e-signature before sending; authentication to the system suffices.

Transmission and Process: How Invoices Are Sent and Received via KSeF

• Accessing KSeF: Taxpayers will access KSeF either via an API integration or through web/mobile applications. Larger companies and software providers integrate their ERP or billing systems directly with KSeF’s API to send invoices in bulk, automatically. Smaller businesses have the option to use the free government tools – a web portal (KSeF online interface) and a KSeF taxpayer mobile app – where they can manually create or upload invoices one by one. There’s also a simplified application called “e-Mikrofirma” for micro businesses. In all cases, users must authenticate (via a digital certificate, trusted profile, token, or electronic seal) to ensure only authorized persons can send invoices on behalf of a company. [dudkowiak.com] [dudkowiak.com], [dudkowiak.com]
• Issuing an Invoice: To issue an invoice via KSeF, a user (or system) transmits the invoice data in the required XML format to the KSeF platform. If using the API, this means the company’s software makes a web request to KSeF with the XML payload. If using the portal, the user might fill in a form or import a file. At the moment of sending, the invoice is considered “issued” by the supplier, pending clearance.
• Real-time Clearance: Upon receiving the invoice data, KSeF performs automatic validations. It checks the schema compliance (are all required fields present and correctly formatted?) and some content rules (e.g., NIP numbers valid, calculations correct). If the invoice passes validation, KSeF registers it and assigns a unique ID. The invoice is given a timestamp (the moment of clearance) and stored in the central database. At this point, the invoice is officially issued and is legally effective. KSeF sends back a confirmation to the issuer (via API response or portal notification) that the invoice is accepted, along with the KSeF ID and a cryptographic hash or QR code. If the invoice fails validation, KSeF rejects it and sends back an error message – the invoice is then not considered issued and the company must correct the data and resubmit. [polishtax.com]
• Delivery to Buyer:
  • For Polish buyers (B2B or B2G): Once cleared, the invoice sits in KSeF and the buyer can access it. Polish buyers will typically also connect to KSeF (via API or portal) to retrieve invoices addressed to them. The buyer’s accounting system can poll KSeF for new invoices by their supplier’s NIP or by date, etc., or the buyer can manually download them. Legally, the invoice is considered delivered to the buyer when it’s available in KSeF (even if the buyer hasn’t yet logged in to view it). Businesses may arrange notifications or automatic fetch processes to get their invoices in a timely manner. This model is a clearance model (as opposed to post-audit): the tax authority is an intermediary that effectively delivers the invoice to the buyer (or at least holds it for pickup). [dudkowiak.com], [dudkowiak.com]
  • For foreign or non-KSeF buyers: As discussed, if the buyer is not on KSeF (e.g. an export customer, or a Polish consumer), the seller must deliver the invoice via other channels. The common practice will be to generate a human-readable invoice (PDF) from the same data and send it by email or allow download on a portal. That PDF must include the QR code or invoice reference so that audit authorities can later match it to KSeF. Notably, KSeF generates a visualization (printable view) of each invoice as well, which can be downloaded and used as the copy sent to such customers, ensuring consistency. [poland-accounting.eu]
• Timeframe for Submission: The Polish VAT law’s general rule is that an invoice should be issued no later than by the 15th of the month following the month of supply. With KSeF, invoices will usually be issued much sooner (typically at the time of the transaction or shortly after). The system is effectively real-time: in practice, businesses are expected to transmit the invoice on or very near the date of the transaction. The law doesn’t force a specific “X hours” rule in normal operation, but commercial reality does – buyers will want their invoices immediately, and VAT must be accounted for. However, there is a specific provision for delays when offline mode is used: [polishtax.com]
  • If a company issues an invoice in Offline mode (Offline24) due to a technical problem, they have up to 24 hours (until end of the next business day) to send it to KSeF after issuing it offline. For example, if on Day 1 the internet was down and the company made a sale, they can generate an invoice internally and give it to the customer. By Day 2 (when online again), they must upload that invoice to KSeF. The law specifically allows this grace period so that business doesn’t halt due to connectivity issues. [crowe.com], [sovos.com] [crowe.com]
  • If KSeF itself is down (system outage on the government side), similar rules apply: an official notice will announce the outage, and invoices issued during it must be sent once the system is back, by a specified deadline (likely also next day). This ensures that even if the system has downtime, invoicing can continue and data will be synced promptly after.
• Offline Workflow: In any offline scenario, the invoice given to the buyer (outside KSeF) must contain either the full data or later be replaced by the official version with QR. The new regulations clarify offline handling to avoid duplicate or missing invoices.
• Receiving & Recording: From the buyer’s perspective, when they retrieve an invoice from KSeF, that invoice is already authenticated and final. They can import the XML into their accounting system (many will convert it to a readable format or directly to an accounting entry). There is no need for the buyer to perform additional verification steps (like checking digital signatures) since the trust is provided by KSeF. One benefit frequently touted by authorities is that buyers won’t risk losing invoices or receiving fraudulent invoices, because they only accept what’s in KSeF – if someone tries to send a fake invoice outside the system, it simply isn’t the legal invoice. [grantthornton.de]

Deadlines for Data Transmission

• For normal operations, companies should submit invoices to KSeF immediately when they issue them (which usually means on the invoice date itself). In any event, submitting by the statutory latest issuance date (15th of next month) would be required if an invoice somehow was issued at that latest moment – but such cases will be rare in practice. [polishtax.com]
• As mentioned, in offline cases (system downtime or no connectivity), the data must be transmitted within 24 hours of issuance (next working day deadline). If this is not done, the invoice that was given offline may be considered not properly reported, which could trigger penalties. [crowe.com], [sovos.com]
• Periodic reporting of non-KSeF transactions: For sales that are outside KSeF (like B2C receipts), Poland currently requires reporting them through the monthly VAT return and the JPK_V7M (SAF-T) file by the 25th of the following month. That process remains unchanged for now. There is no new “e-reporting portal” for those because Poland has already been using SAF-T files as a form of e-reporting for VAT. However, with KSeF in place, the government has indicated it will look at streamlining VAT returns. They might reduce the content of the SAF-T file or eliminate the separate requirement to list each invoice in it (since KSeF would make listing B2B invoices redundant). The Ministry of Finance even mentioned the possibility of eventually eliminating the need to submit the JPK_FA (invoice listing) on demand, because KSeF provides that data continuously. [gov.pl], [polishtax.com] [gov.pl]
• Buyer reporting: Buyers don’t have to “report” purchase invoices – they just ensure they download them. The act of the seller putting it in KSeF constitutes reporting of that transaction to the authorities. For cross-border purchases where the seller didn’t use KSeF (like import of services), the buyer will continue to report those via the VAT return (by doing a reverse charge entry).

Penalties for Non-Compliance

• No Penalties Until 2027: As noted, there will be no fines or penalties for KSeF-related violations in 2026 (the grace period). This was a deliberate decision to allow businesses to adjust without fear of punishment for early mistakes. So, throughout 2026, if a company slips up (e.g., forgets to use KSeF for a certain invoice or submits something incorrectly), the tax authorities will not levy the special KSeF fines (though general penalties for severe tax evasion could still apply in extreme cases). This grace period ends on 31 December 2026. [crowe.com]
• Penalties from 1 January 2027: Starting in 2027, financial sanctions can be imposed for violations. The amended Article 106ni of the Polish VAT Act (as introduced by the 2025 law) specifies these penalties. Key points of the penalty regime: [txb.pl]
  • A penalty up to 100% of the VAT amount shown on the invoice can apply if a required invoice was not issued via KSeF. In other words, if an invoice that should have gone through KSeF was instead issued on paper or email outside the system, the fine could be equal to the VAT on that invoice (essentially doubling the VAT cost for the supplier). [txb.pl]
  • If an invoice didn’t show VAT (for instance, a zero-rated export or a B2C invoice where prices are VAT-included without a separate line), the fine can be up to 18.7% of the total invoice gross value. The 18.7% figure effectively mirrors the 23% VAT rate proportion (since 23% of a net equals ~18.7% of the gross). [txb.pl]
  • These are maximum caps; actual penalties can be lower. The law gives tax authorities discretion to consider circumstances. Minor or first-time breaches might get a smaller fine (or just a warning), whereas systematic neglect could incur larger fines. The authorities will weigh factors like the severity and frequency of the offense, whether it was deliberate, whether the company tried to correct it, and the company’s size/financial situation when deciding the fine. [txb.pl]
  • Penalties also cover failure to comply with offline invoicing rules – e.g., if you issue an invoice offline due to an outage but then don’t upload it within the next day, that can trigger the fine. Also, issuing an invoice during a KSeF outage that doesn’t meet the required criteria (format, etc.) or any non-compliant document flows can be penalized. [txb.pl]
  • There is a procedural element: once a penalty is assessed, the taxpayer will be notified and typically given only 14 days to pay it (since it’s an administrative fine, not a court fine). [txb.pl]
• No Criminal Liability: The law clarifies that these are administrative (financial) penalties, not criminal charges. So failing to use KSeF is not a criminal tax offense by itself; it’s treated like a regulatory fine. This also means no penalty points or personal criminal records for directors – just a monetary sanction on the company (or person). [txb.pl]
• Other Consequences: Aside from direct fines, a hidden “penalty” is that an invoice not issued via KSeF may simply be considered invalid for VAT deduction. A customer might refuse to accept an invoice that isn’t in KSeF (because they know it’s not compliant). So non-compliance could also mean business partners scolding the supplier and demanding a proper invoice (which can be a business penalty in lost goodwill or delayed payments). Additionally, if a company tried to avoid reporting sales by not using KSeF, that’s essentially tax evasion – standard tax evasion penalties (which are much higher and can include criminal charges) would apply in such fraudulent scenarios. So the KSeF-specific fine is more for technical non-compliance, not a license to hide sales.
• Enforcement: Starting 2027, Polish tax offices will incorporate KSeF compliance checks into audits. Since KSeF data is centralized, it will be easy for them to spot if a company had gaps (e.g., issued an invoice series number that never showed up in KSeF). We can expect automated notices if an invoice appears referenced in a contract or bank transfer but isn’t in KSeF. But again, 2026 will be used to educate; actual penalization will get going from 2027.

Archiving and Storage Requirements

• Central Archive by Tax Authority: All invoices submitted to KSeF are stored in the central system. The Ministry of Finance has committed to storing (archiving) all e-invoices in KSeF for 10 years from the date of issuance. In fact, one of the touted benefits of KSeF is that it “eliminates the risk of losing invoices” because the government will keep them safe for a decade. This 10-year period covers the Polish statute of limitations for VAT (5 years from year’s end) with a comfortable buffer. So, for 10 years, the authoritative copy of each invoice is accessible in KSeF, serving as an official archive. [grantthornton.de], [crowe.com] [crowe.com]
• No Need for Duplicate Storage: Because of this central archive, businesses are not required to maintain a separate archive of invoices for tax purposes. The Polish VAT Act traditionally required keeping invoices for 5 years. Now that KSeF will do this (and even double that duration), the law has effectively removed the burden from taxpayers to store their sales invoices themselves. A Grant Thornton analysis highlights that a key change is “removing the necessity for businesses to archive e-invoices, as they will be stored in KSeF for 10 years”. This means tax auditors, if they want to see an invoice, can pull it from KSeF directly rather than asking the company to produce it from their records. [grantthornton.de]
• Accessibility: Taxpayers will have access to their invoices in KSeF during that 10-year period. Through the KSeF portal or API, you can retrieve past invoices at any time. This is useful not just for audits but also for internal purposes (reprinting an old invoice, etc.). After 10 years, the system may purge older invoices (unless laws change to extend it). It’s not entirely clear if after 10 years the responsibility reverts to the company, but likely companies will export and save invoices before they disappear if needed for longer (for example, some regulations or contract disputes might require keeping records for more than 10 years in certain cases).
• Recommendation for Businesses: While legally you might not be obliged to maintain your own archive, it’s still recommended to have backups. Relying 100% on the government system isn’t risky in the 10-year window (the data will be there), but practical access or business needs might prompt keeping a local copy. For example, accounting systems will typically store invoice copies or at least the accounting entries. Also, if a company wants to analyze its past invoices beyond what KSeF’s interface allows, having them in an internal database is useful. An expert guide suggests that businesses should implement their own secure archive for convenience and integrity, even though KSeF provides a basic 10-year archive. [aprosoftwa…utions.com], [aprosoftwa…utions.com]
• Archiving for Non-KSeF invoices: For transactions still outside KSeF (e.g. B2C receipts, etc.), the traditional archiving rules remain. For instance, cash register receipts must be stored in accordance with cash register regulations (often as electronic journal or printouts for a period). Any invoices a business issues or receives outside KSeF (few in number) should be kept in whatever form the law requires (generally 5 years as well). However, as KSeF’s scope is nearly comprehensive, this is a minor side aspect.
• Security and Authenticity: In the electronic world, archiving isn’t just about storage but also ensuring the integrity and authenticity of the invoices over time. KSeF addresses this by storing the original data with digital signatures/timestamps. So an invoice pulled out of KSeF years later can be verified as exactly what was originally issued (no tampering). If a business stores its own copies, they should ensure those are the exact originals (e.g., by downloading the XMLs or using the hash/QR to confirm integrity). Polish regulations already required ensuring e-invoices are stored with integrity and legibility; KSeF largely covers that requirement by design.
• Legal Acceptance: An invoice stored in KSeF is considered by law to be the official copy. If a buyer loses the PDF they were sent, they or the seller can always retrieve the invoice from KSeF and it’s considered valid. There is no obligation to provide paper duplicates, etc. The ministry even noted that one benefit is businesses won’t need to issue duplicates because e-invoices “will always be available” to both issuer and recipient in the system. [gov.pl]

• As long as your invoices are in KSeF, you meet the VAT Act’s record-keeping rules. [grantthornton.de]
• KSeF will keep them for 10 years, covering the standard retention period. [crowe.com]
• You should ensure access to KSeF data and possibly keep your own copy for convenience, but legally the burden (and cost) of archiving is lifted – one of the clear advantages of the system. [crowe.com]

Pre-Filled VAT Returns (Are They Available?)

• Cross-Checking vs Pre-filling: In the immediate term, the main benefit is cross-checking. Tax authorities can very easily compare a company’s VAT return with the sum of its KSeF invoices. In fact, an official noted that authorities will “verify data declared in VAT returns against invoices stored in KSeF” more efficiently. This means errors or omissions might be caught quickly, and fraudulent claims detected (e.g., claiming input VAT on an invoice that isn’t in KSeF, or under-reporting sales that KSeF shows). So, while the taxpayer still submits the return, the authorities have a much better picture to validate it behind the scenes. [polishtax.com]
• Possible Future Pre-filled Returns: It is anticipated that after some time, Poland might start offering a draft VAT return to taxpayers, populated with the data from KSeF (and other sources for things like imports). This has happened in Italy – after e-invoicing, Italy began providing annual VAT report drafts and even monthly communication drafts. Poland has not formally announced such a service yet. They did mention that full visibility of transactions “gives the possibility of implementing further simplifications in VAT settlements”, which could hint at pre-filled returns or doing away with certain filings. So, perhaps in a few years, Polish businesses might see a world where the monthly VAT return is auto-generated by the system and the business just confirms or adjusts it. [gov.pl]
• EC Sales List and SAF-T: With all B2B invoices in KSeF, authorities have the data that would normally be in an EC Sales List (VAT-UE) for intra-EU trade. We might see that declaration being phased out once they are confident in KSeF data capture. Similarly, the JPK_V7M (SAF-T) currently includes an invoice-by-invoice listing; this could be simplified to just summary numbers if invoice-level data is already with the tax office. In fact, one benefit explicitly noted is that a KSeF user “will not have to submit JPK_FA [the detailed invoice register] on demand” because that info is in KSeF. That implies some obligations will be lifted. [gov.pl]
• Input VAT and Purchases: While sales data is straightforward (they have every invoice you issued), input VAT data is trickier since it includes invoices you received (which KSeF will also have if the supplier was Polish and in KSeF) as well as things like imports or travel expenses (which might not be in KSeF). The authorities do get domestic purchase invoices (because they’re someone else’s sales invoice in KSeF). Technically, they could pre-fill your purchase ledger from KSeF (like Italy started doing with its “pre-fattura” system). That could lead to a draft of your VAT return’s credit side too. But issues like missing invoices (if a supplier was late in KSeF) or invoices you don’t want to claim could arise, so it needs careful implementation.
• Current State: Until at least the end of 2026, businesses should operate under the assumption that they must file VAT returns as normal. The first few periods of mandatory e-invoicing will likely still see companies compiling their output VAT from their systems (though it should match KSeF exactly) and their input VAT (from KSeF plus any non-KSeF invoices). The Polish tax authority will likely run comparisons in the background and only step in if inconsistencies are found, rather than giving you a filled form to accept or reject.

• Polish VAT Act Amendments: The mandate is implemented via amendments to the Act of 11 March 2004 on tax on goods and services (VAT Act), notably by the Act of 29 October 2021 (which allowed voluntary KSeF) and the Act of 5 August 2025 which made it obligatory. Article 106o and 106ni of the VAT Act (after amendment) cover the obligation and penalties. (See the Polish Journal of Laws 2025, item 775 for the consolidated text.) [txb.pl], [txb.pl]
• EU Council Decision: Council Implementing Decision (EU) 2022/1003 of 17 June 2022 – this allowed Poland to introduce mandatory e-invoicing by derogating from Articles 218 and 232 of the VAT Directive. [ec.europa.eu]
• Ministry of Finance Resources: The Polish Ministry of Finance provides official info on KSeF on its websites. The KSeF portal (ksef.podatki.gov.pl) has documentation and an info brochure. Press releases (e.g., MF announcement on 30 June 2023) detail the legislative progress and features of KSeF. The ministry’s podatki.gov.pl site and the Gov.pl finance ministry news section contain updates (in Polish) on KSeF regulations and the rollout schedule. [kpmg.com] [gov.pl], [gov.pl]
• Technical Documentation: The Ministry has published the logical structure of e-invoices (FA(3) schema) and an extensive KSeF 2.0 manual (released September 2025) covering how to use the system. These are available on the official KSeF website. [kpmg.com]
• Tax Authority Guidance: The Krajowa Informacja Skarbowa (KIS) has issued interpretations, for example confirming how foreign transaction invoices should be handled. These clarifications (like the requirement of QR codes on invoices for foreign buyers) are part of the legal guidance around KSeF’s implementation. [poland-accounting.eu]
• EU Commission eInvoicing Factsheet: The European Commission’s 2025 country sheet for Poland provides a summary of e-invoicing status, confirming scope and mandate dates. [ec.europa.eu], [ec.europa.eu]
• Professional Analysis: Big 4 and other consulting firms have published alerts (e.g., KPMG TaxNewsFlash August 2025, EY Global Tax Alert April 2025) confirming the timeline and key provisions. These align with the final legislation. [kpmg.com] [globaltaxnews.ey.com]