KSeF in a small service business: which dates apply and what changes in daily work

Three dates that organize the KSeF obligation

The obligation was introduced in stages. For a small service business, two dates matter: 1 February 2026, when KSeF covered taxpayers with sales exceeding 200 million PLN (with tax) in 2024, and 1 April 2026, when the rest joined. The third date — 1 January 2027 — ends the exception for the smallest; the portal shows it using the example of a flower seller. Everything in one table:

The element that is most often missed: receiving invoices also applies to a company that issues invoices outside the system itself — you look for invoices from contractors in KSeF, not in your email inbox. That is why, even below the limit, it is worth having access to the system. The scope of mandatory KSeF is explained by the Ministry of Finance portal.

The 10,000 PLN limit: calculate it on your own invoices

The exception works monthly: sales with tax on invoices issued in a given month count. Only invoices that must go to KSeF are included — without amounts from cash registers and receipts with NIP up to 450 PLN and without consumer invoices. The invoice date, not the service completion date, qualifies the month.

You can do a quick calculation using the formula: monthly_sales = number_of_invoices × average_gross_amount. An example with made-up numbers: 4 invoices of 2,200 zł gross make 8,800 zł — within the limit; a fifth one brings the month to 11,000 zł and the limit is exceeded. Substitute your own numbers.

The mechanics of exceeding: in the month you exceed the limit, the invoice that exceeds it and all subsequent ones must be in KSeF, and dropping below 10,000 PLN in the next month does not restore issuing outside the system. The flower seller from the portal example — three invoices per month at 1,500–2,500 PLN gross — stays within the limit throughout 2026, but from 1 January 2027 the obligation fully applies to her. Details are gathered in the FAQ "Below 10,000 PLN".

Documents that do not go to KSeF at all

The following are not sent to the system:

• proforma invoices,
• internal invoices,
• internal proofs,
• credit notes,
• debit notes.

A separate change: from 1 February 2026, the regulations on corrective notes were repealed, so you do not issue them in KSeF or outside the system. If the accounting office corrected errors with notes, clarify with them how to report corrections now — the tool has changed, not the obligation for correctness.

Which "invoices" in your business are actually proformas

In services, documents easily get mixed: an "invoice" sent by email before payment is often a proforma, and a sales invoice is created only after the transfer. Review the documents from the last month and name each one correctly — proforma does not go to KSeF, sales invoice is subject to the obligation. An hour of this ordering saves questions in the first month in the system; confirm with the accountant which document is which.

Receipt with NIP from the cash register instead of invoice in KSeF

Until the end of 2026, cash registers remain in play: a fiscal receipt with the buyer's NIP worth up to 450 PLN (or 100 euros) is considered a simplified invoice and does not go to KSeF. At a service reception: a company client pays on site, provides the NIP, the person at the cash register issues a receipt with NIP — this is the sales document. Amounts from the cash register do not count toward the 10,000 PLN limit, so this path does not eat up the exception. What happens with cash registers from 1 January 2027 — check the current position of the KSeF portal.

Individual clients: invoice in KSeF only voluntarily

Sales to private individuals is a separate path: B2C invoices in KSeF are voluntary — both before 1 February 2026 and after that date — and consumer invoices do not count toward the 10,000 PLN limit. A clinic or salon issuing an invoice at the client's request continues this path the old way. Details are described in the FAQ for consumers and natural persons.

Daily invoice issuing after transitioning to KSeF

An e-invoice is an XML file compliant with the template, sent to the system, which KSeF assigns a unique number to. The recipient with NIP finds it themselves — you do not send it by email or print it (except for statutory exceptions), and in KSeF it is archived for 10 years. You issue in a financial-accounting program integrated via API or in the Ministry of Finance's free tools — the Online Taxpayer Application and Mobile Application. In a small service business, the entire circulation turns into one path:

Where to get the buyer's NIP

An invoice in KSeF starts with data, and in services data is collected at the order stage, not at invoicing. If NIP and address land in the client card at the first inquiry, the issuer does not re-type anything from a piece of paper. About one source of client data is CRM and automations, about what can be handed over to the system is process automation in the company, and about the numbers worth extracting from them is reporting automation.

Permissions: who issues invoices on your behalf

In KSeF, the taxpayer authenticates or a person or entity they designate — for example, an accounting office that can indicate its employees. Authentication uses Trusted Signature, qualified signature, qualified seal, token or KSeF certificate; PESEL alone is not enough. It is worth arranging in a table:

A principle worth guarding: access is granted and revoked on the permissions side, not by sending a password to someone — this is how API works in Aura. Write down who currently issues invoices on your behalf — a list on one sheet is a ready audit.

When the internet does not work: offline24 mode

Failure does not block invoicing. Offline24 mode allows any taxpayer to issue an e-invoice outside KSeF — compliant with the structured invoice template, for example when there are network problems — and send it no later than the next business day. You mark the invoice with two QR codes, and for the second you need a KSeF certificate downloaded earlier. The portal also distinguishes offline mode during Ministry of Finance maintenance (sending the day after the break ends) and emergency mode during a failure announced in the BIP (7 business days). All procedures are described in the KSeF 2.0 questions and answers.

Who in the company is responsible for sending the invoice

The emergency procedure only works when someone knows it by heart. Designate a person who, when there is no internet, issues invoices outside the system, and ensure the KSeF certificate for the second QR code is downloaded earlier, not on the failure day. One line in the office procedure closes the topic.

Penalties for errors in KSeF postponed to 1 January 2027

The KSeF portal informs that penalties for errors in the system have been postponed to 1 January 2027. For a small business, this is not a signal "you can slow down" — it is a postponement of sanctions in time: the obligation to issue and send works today, the consequence of error is postponed. Practically: the last months of 2026 are suitable for practicing the circulation without criminal pressure — you still correct errors, just more calmly. Whether an error occurred in your case and how to fix it, the accountant or tax advisor will assess.

Company review by 31 December 2026: do it yourself

Before the year ends, go through six steps in the company — each takes fifteen minutes:

1. Sum the sales from mandatory invoices for the last three months by issue date and compare each month to the 10,000 PLN limit.
2. List all programs that issue invoices for you, including those from the accounting office.
3. Check who actually has permissions in KSeF on your behalf, and cross out people who should no longer be there.
4. Ask the software provider whether the invoice gets a KSeF number, where to find it, and whether payment status returns to the system.
5. Agree with the accounting office on the division of roles: who issues, who books, who sends in offline mode.
6. Practice the offline24 scenario on a trial invoice before it catches you at work.

These numbers can be on one screen instead of in three spreadsheets — Dashboards; the summary can come on its own before you open the panel — AI Reports. And when there is too much manual retyping for the evening, the thresholds for implementation are described in where to start automation in a small business.

What invoicing looks like when the system runs it

A closed order in CRM can go to an invoicing program connected to KSeF without retyping client data — that is a job for integrations. What comes back to the client card (KSeF number, payment status) depends on what your invoicing program exposes — we check that at the start, before promising anything.

The human stays with decisions: order valuation, conversation with the client, discount consent, assessment of whether the case requires a lawyer. The system takes over data transfer and ensures no invoice hangs without a number. On the tools side: Finance shows revenues, costs and margin in real time, Integrations connect the invoicing program with the rest of the company, and CRM and automations keep one client file. Requirements for an invoicing system with KSeF are laid out in invoicing automation, and the costs of such projects — in the 2026 ranges. See how it works in practice — start with Finance.

Frequently asked questions

If I sell for less than 10,000 PLN per month, do I have to issue invoices in KSeF?

Until 31 December 2026, yes — you issue outside the system if sales with tax on mandatory invoices does not exceed 10,000 PLN in the month. In the month of exceeding, that invoice and all subsequent ones must be in KSeF, and returning outside the system is no longer possible. From 1 January 2027, the obligation applies to small entrepreneurs without a limit — the flower seller example shows this.

Does a receipt with NIP from a fiscal cash register replace an invoice in KSeF?

Until the end of 2026, a fiscal receipt with the buyer's NIP worth up to 450 PLN (or 100 euros) is considered a simplified invoice and you do not have to send it to KSeF. Amounts from cash registers and receipts also do not count toward the 10,000 PLN limit. What happens with cash registers from 1 January 2027 — check the current position of the KSeF portal.

Do I have to issue invoices for private individuals in KSeF?

No. Issuing B2C invoices in KSeF is voluntary both before 1 February 2026 and after that date. Consumer invoices also do not count toward the 10,000 PLN limit.

What to do with an invoice when there is no internet?

Use offline24 mode: issue an e-invoice outside KSeF, compliant with the structured invoice template, and send it to the system no later than the next business day, marked with two QR codes. During Ministry of Finance maintenance, offline mode applies, and during a failure announced in BIP — emergency mode with a longer deadline.

Will I already face penalties for errors in KSeF?

The KSeF portal informs that penalties for errors have been postponed to 1 January 2027. The postponement does not remove the obligation to issue and send invoices — only the penalties for errors have been moved in time. Whether an error occurred in your case and what to do with it, the accountant or tax advisor will assess.

Who can issue invoices in KSeF on my behalf?

Besides you — a person or entity you designate, for example an accounting office; it can indicate its employees. Authentication requires Trusted Signature, qualified signature, qualified seal, token or KSeF certificate — PESEL alone is not enough.