KSeF does not just apply to invoices you issue to your customers. Starting 1 February 2026, companies must also receive invoices issued to them through the system. This requirement came into effect earlier than the invoicing obligation for some businesses.
For an online shop, this means a shift in handling purchase invoices. A document from a Polish supplier might no longer arrive by email or appear in your existing panel. It goes to KSeF, and your accounting system, ERP, or another integration has to retrieve it from there.
Simply connecting WooCommerce, PrestaShop, or your sales platform to issue invoices in KSeF does not mean expense invoices are automatically collected.
Invoices must be received in KSeF from 1 February 2026
The KSeF implementation schedule separated issuing and receiving invoices.
From 1 February 2026, the requirement to issue invoices via KSeF applied to the largest taxpayers whose sales value, including VAT, exceeded PLN 200 million in 2024. From 1 April 2026, it expanded to other businesses, except for the smallest enterprises covered by a temporary exemption.
Until the end of 2026, a taxpayer can still issue invoices outside KSeF if the total value of sales documented by such invoices does not exceed PLN 10,000 gross in a given month. From 1 January 2027, mandatory KSeF will also cover this group.
Receiving invoices works differently. The obligation to receive invoices via KSeF began back on 1 February 2026.
This means a business can find itself in a period where it does not yet have to issue invoices in KSeF, but is already receiving documents through it from its suppliers.
Invoices might not arrive by email anymore
If a supplier issues an invoice in mandatory KSeF to a domestic taxpayer with a Polish tax identification number (NIP), they are under no obligation to deliver an extra copy via email or on paper.
They can, of course, provide a PDF preview, but the primary place to receive the document is KSeF.
In practice, this applies to goods purchased from Polish wholesalers, courier services, hosting, software, technical support, or other domestic services used by your store.
If your accounting process previously relied on a invoice@company.com inbox, some documents may simply stop landing there.
However, this does not mean the invoices were never issued or that your company hasn't received them.
An invoice is legally received even before you download it
This is one of the most critical changes regarding document workflow.
For a structured invoice received via KSeF, the legal date of receipt is generally the day the system assigns it a KSeF number.
It does not matter when an employee logged into the system, when the integration fetched the document, or when the accountant actually saw the invoice.
If a supplier submitted an invoice in the evening and the KSeF number was assigned the next day, that following day counts as the date of receipt.
That is why downloading purchase invoices shouldn't rely on someone remembering to log into KSeF manually. In an online shop handling a higher volume of documents, this should be a routine, automated recurring process.
KSeF does not send notifications for new invoices
KSeF does not work like an email inbox that sends an alert whenever a new document arrives. The Ministry of Finance states that the system sends no automatic notifications when a new invoice is received.
Invoices can be checked using Ministry of Finance tools or pulled via the KSeF API into your own systems.
For an online shop, this means you need to set up the intake process yourself. Your accounting system, ERP, or a dedicated integration should regularly check KSeF and fetch incoming documents.
The lack of an email from a supplier can no longer be taken as a sign that an invoice has not been issued yet.
An invoicing integration won't necessarily receive invoices
This is a frequent misunderstanding when integrating online shops with KSeF.
A business deploys a module that pulls orders from WooCommerce or PrestaShop, generates an invoice, and pushes it to KSeF. Sales invoices work smoothly, so the team assumes KSeF is completely taken care of.
However, receiving purchase invoices is a completely separate process.
KSeF permissions also distinguish between issuing and accessing invoices. The system or user profile responsible for fetching documents must have the proper read permissions.
That is why, during implementation, it is not enough to verify that your shop can send a valid document. You also need to determine where purchase invoices end up and which system is responsible for pulling them.
Base will not pull expense invoices from KSeF for you
A good example is Base, formerly known as BaseLinker. Its KSeF integration is built to send documents issued inside Base.
According to Base documentation, the integration does not retrieve expense invoices or invoices issued in other systems.
This is not a flaw in the integration itself. It simply shows that the system handling your sales does not also have to be the system managing your purchase document workflows.
A single business might run WooCommerce or PrestaShop as its order source, Base to manage sales and shipping, and an accounting platform that retrieves purchase invoices from KSeF.
What matters most is clear division of responsibilities. If every system handles only outbound sales and none collects inbound purchases, the invoices will exist in KSeF, but won't automatically enter your accounting workflow.
WooCommerce and PrestaShop do not solve this automatically
The core e-commerce engine should not be treated as a central accounting hub just because it can generate a sales receipt or invoice.
In WooCommerce, invoices are usually handled by a plugin or an external tool. In PrestaShop, some documents can be created alongside orders, but real-world setups often connect sales to an ERP, a warehouse management system, Base, or an accounting suite.
KSeF forces you to streamline this pipeline.
It is best practice to designate one system responsible for issuing sales documents and one responsible for fetching and storing purchase documents. They can be the same tool, but they don't have to be.
Check issue and read permissions
An integration should only have the permissions it actually needs.
A system issuing invoices needs permission to submit them to KSeF. An accounting system retrieving purchase documents needs read access.
When auditing your integrations, map it out clearly: which system issues documents, which one pulls them, what permissions each holds, and what happens to a document once it is retrieved.
If you cannot point to the specific system responsible for fetching purchase invoices, there is a good chance your setup is only halfway done.
Not all purchase invoices will be in KSeF
Once you implement KSeF, you cannot stop monitoring your other document channels.
The mandate to issue invoices in KSeF does not apply to every seller or every transaction type. For e-commerce, foreign suppliers are an essential exception.
Your shop might receive invoices for international SaaS tools, advertising, marketing software, hosting, cloud infrastructure, or other services provided by companies outside Poland. These will continue to arrive through your usual channels.
In practice, you will need to handle KSeF alongside non-KSeF invoices simultaneously for the foreseeable future.
When vetting a vendor, look at the legal entity listed on the invoice, not just the brand name. An international brand may bill different services through different regional subsidiaries.
Tax IDs in B2B orders matter more than ever
If your store handles B2B sales, pay special attention to how the buyer's NIP is passed along.
A tax ID should not be treated merely as text printed onto a PDF later. The integration generating the FA(3) schema must place it into the designated buyer data field.
This is crucial for the invoice to be properly matched and made available to the buyer inside KSeF.
If your shop uses a custom B2B checkout, check the NIP validation, customer data mapping, and how that information is transferred to your invoicing software.
Corrective notes are gone
From 1 February 2026, regulations covering buyer-issued corrective notes (noty korygujące) have been repealed. They cannot be issued inside KSeF or outside it.
Any mistake in the buyer's details must be corrected by the seller using an official corrective invoice (faktura korygująca).
This also impacts automated B2B sales. A wrong NIP entered by a customer during checkout will require a manual correction on the seller's end, making it well worth catching as many errors as possible directly in the checkout form.
Consumer sales follow different rules
Invoices issued to individual consumers are not subject to mandatory issuance in KSeF. However, a seller can choose to issue them via the system voluntarily.
In that case, the seller must provide the consumer with appropriate access to the document. The Ministry of Finance allows for sharing the invoice via an agreed method, and direct access through KSeF relies on a QR code and the credentials needed to download the file.
A store catering to both retail and corporate customers should separate these two checkout flows right from the start.
What to check in your online shop after rolling out KSeF
- Define where sales invoices originate. WooCommerce, PrestaShop, Base, your ERP, or your accounting software should each have a clearly defined role.
- Verify who retrieves purchase invoices. Sending sales documents to KSeF is not enough on its own.
- Review access permissions. The tool responsible for intake must have the rights to read the right documents.
- Audit your previous invoice channels. Check your accounting inbox to see which domestic suppliers have stopped-or will stop-sending invoices by email.
- Maintain workflows for non-KSeF documents. Foreign invoices and other exempt documents will still need a separate handling flow.
- Validate NIP inputs in your B2B checkout. Review both form validation and field mapping into the invoice schema.
- Determine where documents are archived. KSeF stores invoices for 10 years starting from the end of the year they were issued, but your company may still need its own archive linked to orders, deliveries, and bookkeeping.
KSeF is more than just a new way to issue invoices
In an online shop, it is easy to focus only on sales: an order comes in, the system creates an invoice and uploads it to KSeF. But that is only half the equation.
The purchase flow is just as vital. An invoice can be legally received in KSeF without ever hitting your email and before anyone on your team has seen it.
Approaching KSeF the right way means using it as an opportunity to clean up the entire document pipeline between your store, sales manager, warehouse, ERP, and accounting.
At DOCK, we handle Online shops as well as System integrations. For KSeF, we can review more than just the API connection: we look at how documents flow between your shop, Base, ERP, and accounting.
If you want to ensure your store is set up to both issue and receive invoices correctly through KSeF, get in touch. We can review your current setup and identify where documents might be falling through the cracks.
