Invoicing software in 2026 — KSeF, free tools and paid plans

Invoicing software in 2026 is above all a client of KSeF, the National e-Invoicing System (Krajowy System e-Faktur). From 1 April 2026 all businesses except the smallest issue invoices in KSeF, and from 1 January 2027 there are no exceptions. KSeF itself costs nothing, and the Ministry of Finance (Ministerstwo Finansów, MF) provides free apps for issuing and receiving invoices. Paid software is therefore not a condition of entering the system. What it sells is convenience: automatic download of purchase invoices (KSeF notifies no one about them), integrations with your shop and bank, bookkeeping, a warehouse, several users.

So you choose invoicing software by two questions, not by brand: how many invoices you issue a month, and whether you want to keep the books yourself or hand them to an accounting office. Free plans of commercial programs have limits — for example three invoices — which are fine for the first clients and stop being enough once sales become regular. Data security matters too: at the end of September 2026 an incident hit Fakturownia, one of the popular programs, so we end with a checklist, not a vendor name.

KSeF: who, from when, and with what exception

The duty to issue invoices in KSeF now covers almost every business that issues B2B invoices. The Ministry of Finance sets it out on the page When you have to issue invoices in KSeF (read 2.10.2026): the duty came in stages — from 1 February 2026 for firms whose 2024 sales exceeded PLN 200 million (including VAT), from 1 April 2026 for the rest. In addition, until 31 December 2026 you may still issue invoices outside KSeF (paper or electronic) if, in a given month, the total of sales including VAT on such invoices does not exceed PLN 10,000. From 1 January 2027 KSeF is mandatory also for those who used that exception.

The PLN 10,000 exception works by a few rules that the Ministry explains on the page Below PLN 10,000:

• What counts is the total including VAT on invoices that would have to go to KSeF. You don't count cash-register invoices, receipts with a NIP up to PLN 450, or invoices to consumers.
• The month is set by the invoice's issue date.
• Once you exceed the limit, you enter KSeF from the invoice that crossed it. A weaker later month undoes nothing: the fact that the limit was not exceeded in the third month "has no significance any more".
• Cash-register invoices and receipts with a NIP up to PLN 450 stay outside KSeF until 31 December 2026.

Legal form does not exempt you from KSeF. On the page for sole traders and SMEs the Ministry says it outright: "legal form makes no difference". Invoices in the system are issued by every taxpayer, VAT-registered or exempt, who is obliged to issue an invoice. A sole proprietorship is not treated differently from a company.

Receiving invoices through KSeF is mandatory for everyone from 1 February 2026. The Ministry adds that a KSeF invoice needs no acceptance by the recipient: it is deemed received when the system assigns it a number. Invoices to consumers are outside the duty — according to the page for consumers and private persons, issuing B2C invoices in KSeF "is voluntary". Issuing through KSeF an invoice to a business owner for private purchases is voluntary too.

One more date concerns payments, not issuing. From 1 January 2027 Art. 108g of the VAT Act applies (the Ministry gives the date): an active VAT payer who pays another active VAT payer by bank transfer for a KSeF invoice puts its KSeF number, or the batch identifier assigned by the system, in the transfer title.

The EU's ViDA package, Council Directive (EU) 2025/516, in force since 14 April 2025, is a separate layer on top of national schemes like KSeF. It standardises the e-invoice format (EN 16931) and introduces digital reporting for cross-border B2B transactions from 1 July 2030, with existing domestic systems to align with it by 1 January 2035. For an invoice issued in Poland, the dates that matter are the KSeF ones above.

Peppol is an international e-invoicing network: an invoice sent through one provider's access point reaches a recipient connected through another provider, without a direct point-to-point connection between the two businesses. Many invoicing tools sell Peppol connectivity as a paid feature.

The Ministry of Finance's free tools

You don't need paid software to issue invoices in KSeF. Asked whether you must have it, the Ministry answers: "No. The Ministry of Finance provides free tools". It names two KSeF applications, and on the page for sole traders and SMEs adds a third route:

• The KSeF Taxpayer Application (Aplikacja Podatnika KSeF, the online version) is, according to the Ministry, for "using the system, managing permissions, tokens and eventually also KSeF certificates, previewing invoices and downloading the UPO" (the official confirmation of receipt).
• The KSeF Mobile App (Aplikacja Mobilna KSeF), available from 1 February 2026, lets you "issue and receive invoices in the system with a smartphone, preview invoices and create a draft invoice".
• e-mikrofirma in the e-Tax Office (e-Urząd Skarbowy). Once the account is linked to KSeF, the taxpayer "can issue and receive invoices in the system and move them directly to the VAT records".

You log in to KSeF with a Trusted Profile (Profil Zaufany), a qualified signature, a qualified seal, a token or a KSeF certificate. A PESEL number alone is not enough.

The most important limit concerns purchase invoices. The Ministry writes: "KSeF does not send notifications. Your software (accounting program, application) must regularly check whether new invoices have appeared". With the free Ministry apps you do that checking yourself by logging in. The invoice is deemed received the moment it gets its number in KSeF, so it does not wait until you notice it.

For outages and breaks the Ministry provides offline modes. In offline24 mode, which according to the Ministry you can also use without internet problems, the invoice must be sent to KSeF by the next working day at the latest. In KSeF unavailability mode, by the day after the break ends. In emergency mode, announced in the Ministry's Public Information Bulletin (BIP), you have 7 working days after the outage ends.

What the Ministry's tools don't do: they don't remind clients about payments and don't connect to a shop or a bank. They don't keep the books either, beyond the VAT records in e-mikrofirma. For a firm that issues a few invoices a month and watches payments itself they are often enough. When one of those things starts to be missing, a paid program starts to pay for itself.

What an invoice must contain

The mandatory elements of an invoice are listed in Art. 106e(1) of the VAT Act, which we cite from the latest consolidated text, Dz.U. 2026 item 1263 (legal status of 26.08.2026). In an ordinary domestic sale an invoice must show:

1. the date of issue;
2. a sequential number, in one or more series, which "uniquely identifies the invoice";
3. the names of the seller and the buyer and their addresses;
4. the NIP (tax ID) of the seller and of the buyer;
5. the date of supply, of performance of the service or of receipt of payment, if different from the date of issue;
6. the name (type) of the goods or services, the unit of measure and quantity, or the scope of the services;
7. the net unit price, any discounts not included in the price, and the net value of the sale;
8. the VAT rate, the net total per rate and the amount of tax per rate;
9. the total amount due.

Some transactions need extra markings: "metoda kasowa" (cash accounting), "samofakturowanie" (self-billing), "odwrotne obciążenie" (reverse charge). The words "mechanizm podzielonej płatności" (split payment) are mandatory when the amount due exceeds PLN 15,000 and the invoice to a taxpayer covers goods or services from Annex 15. For a sale exempt from VAT, the invoice must cite the legal basis of the exemption, for example Art. 113(1) or (9) of the Act. Two rules come from the EU VAT Directive and apply here too: no member state may require invoices to be signed (Art. 229), and amounts may be in any currency as long as the VAT is also expressed in the national currency, which in Poland means złoty (Art. 230).

Simplified invoices for small amounts

For small amounts the provision allows a simplified invoice. If the total amount due does not exceed PLN 450 or €100, the invoice may omit the buyer's name and address and part of the price and value data. It must still allow the tax amount to be determined for each rate (Art. 106e(5)(3)). Para. 6 excludes from this option, among others, an intra-EU supply of goods and a sale where the buyer's NIP is not given. Receipts with a NIP up to PLN 450 stay outside KSeF until 31 December 2026. Whether you are eligible for the VAT exemption in the first place, at the threshold of PLN 240,000 from 1 January 2026, is covered in how much it costs to start a business.

An invoice outside KSeF: QR codes

When you pass a KSeF invoice to the buyer outside the system, its visualisation must carry a QR code. This applies, for example, to a PDF for a consumer or for a client from outside the EU. The Ministry describes it like this: "A QR code is a special graphic mark placed on the visualisation of an invoice. It lets you easily check whether the document is in the system and, after entering additional data, download it from KSeF".

The number of codes depends on the mode in which the invoice was issued. An invoice issued online, or already sent to KSeF, has one QR code with the KSeF number as its caption. An invoice issued offline and not yet sent has two. The first, captioned "OFFLINE", gives access to the invoice and verification of its data. The second, captioned "CERTYFIKAT", "enables verification of the issuer's identity". The second code needs a KSeF certificate of type 2 generated beforehand.

In practice this means one thing: the invoicing program must be able to generate a visualisation with a QR code. If you use the offline modes, it must also support the certificate for the second code. Check this before you choose, especially if you sell to consumers or abroad.

An invoice when you are not a VAT payer

A firm exempt from VAT under the subjective exemption does not have to issue invoices on its own initiative, but must on the client's request. Art. 106b(2) of the VAT Act says a taxpayer is not obliged to issue an invoice for a sale exempt under Art. 43(1), 113(1) and (9). Para. 3 adds that on the request of the buyer of goods or services the taxpayer must issue an invoice — also for such an exempt sale, if the client makes the request within 3 months of the end of the month of supply, performance of the service or receipt of payment.

If you issue such an invoice, it goes to KSeF: the Ministry counts as covered every taxpayer, "VAT-registered and exempt", who issues an invoice. Until the end of 2026 an exempt taxpayer can still use the PLN 10,000 monthly exception. From 2027 that relief disappears.

Where the rules do not require an invoice, you issue a bill (rachunek) on the client's request. It is governed by the Tax Ordinance, consolidated text Dz.U. 2026 item 622. Art. 87 § 1 obliges you to issue a bill "at the request of the buyer or service recipient", and you have 7 days (§ 3). The duty does not exist if the request comes after 3 months from the sale (§ 4). Art. 88 § 1 requires bills to be numbered in sequence and copies kept until the tax liability expires.

Free and paid invoicing tools

A free invoicing program with KSeF exists, but "free" in a commercial offer means a limit. Three of the four popular programs have a PLN 0 plan, and each of them includes KSeF. They differ in what limits the plan: the number of invoices, how often purchase invoices are fetched, or the range of features. The state of the price lists on 2 October 2026:

• [Fakturownia](https://fakturownia.pl/cennik), Micro plan: PLN 0 net, a limit of 3 invoices a month, "KSeF integration", one user. Mind the security incident of 27–28 September 2026, described below.
• [iFirma](https://www.ifirma.pl/cennik): free invoicing up to 3 invoices a month. The vendor declares "full KSeF integration in every package".
• inFakt, the "inFakt KSeF" plan: PLN 0 net for new clients, no document limit, with sending to KSeF and fetching of purchase invoices. On the free plan purchase invoices are fetched once a week, on paid plans every 15 minutes. That is data from our dataset for the SaaS tool cost study of 26 August 2026 — we couldn't re-read inFakt's price list, so check it before choosing.

The fourth popular program, [wFirma](https://www.wfirma.pl/cennik/zarzadzanie-sprzedaza), has no PLN 0 plan. The "Fakturowanie i CRM" package (KSeF integration, "unlimited users", JPK_FA, online fiscal printers) costs PLN 25 net a month, and you get it at no extra charge only together with the Accounting or Full Accounting package.

A limit of three invoices is enough for the first weeks of trading, but a firm with a few regular clients will exceed it quickly. inFakt's plan shows a different kind of limit. Since KSeF does not notify about purchase invoices, how often they are fetched decides how fast you see a supplier's invoice. Once a week is slower than several times a day.

In our study of SaaS tool costs we wrote that KSeF "costs PLN 0". That sentence is true without reservation for the Ministry of Finance tools, which state no invoice limit. In commercial programs PLN 0 means "PLN 0 up to a point". You check that point in the price list before choosing, not after the first blocked invoice.

Paid plans: what you pay for

Prices of paid plans rise with four things: the number of invoices, the number of users, bookkeeping and a warehouse. All amounts below are net prices per month according to the price lists of 2 October 2026:

• Fakturownia: Start PLN 12.49, Standard PLN 28.46, Pro PLN 49.99, Pro Plus PLN 83.46. The price list states: "all prices given are net prices for a 12-month plan". The trial lasts 30 days.
• wFirma: Fakturowanie i CRM PLN 25, Magazyn (warehouse) PLN 40. The amounts are the same on annual and monthly billing. The vendor gives 30 days free at the start.
• iFirma: Faktura+ "at PLN 12.50 a month when paying for 12 months". The full price list "applies to services from 09/2026".

Fakturownia and iFirma quote prices for payment for 12 months. If you prefer to pay monthly, check the price in the price list before buying — Fakturownia doesn't show it next to the annual price.

Prices in this category diverge for a simple reason: three different products are sold under the one name "invoicing program". The first is invoicing alone, which in the basic version is sometimes free or costs from a dozen or so to PLN 25 a month. The second is self-service bookkeeping, where the program keeps the records and the responsibility stays with you. The third is an accounting office in a bundle, where you pay for the accountant's work, which is why prices start above a hundred złoty. So compare plans from the same group, not the cheapest plan of one vendor with the dearest of another. We set out the prices of self-service bookkeeping and packages with an accountant at the same vendors in accounting software for a small business.

Data checklist for invoicing software

Whatever tool you choose, it holds your clients' invoicing data, and that makes its security part of the decision, not an afterthought. The September 2026 case shows it well. Fakturownia published an incident notice ("Update no. 1 of 01.10.2026, 16:00", re-checked on 2 October 2026). It wrote: an unauthorised person gained access to its systems and copied a large part of the database to their own servers; the unauthorised access lasted from about 03:20 on 27.09.2026 to about 17:45 on 28.09.2026. The company adds: "the incident concerns every account in Fakturownia". It reported the breach to the President of UODO (the Personal Data Protection Office, Urząd Ochrony Danych Osobowych) and the incident to CERT Polska and the Police on 29 September 2026, and has sent individual e-mail notices since 1 October. The lesson applies to every provider, not one. Before you commit:

• Check whether the account can be protected with two-factor authentication. If a password alone unlocks every invoice and every client's details, that's a single point of failure.
• Check whether the provider signs a data-processing agreement. Under GDPR, a provider processing personal data on your behalf as a processor should offer a DPA setting out what it does with that data and under what safeguards — GDPR, Art. 28. Ask for the DPA (umowa powierzenia) by name.
• Check whether you can export your invoices and client list at any time. If your own records are locked in, you're no longer just using the tool — you depend on it.

How to secure business accounts more broadly, including the admin account itself, is in protecting company data. Questions worth asking any cloud provider holding business data are gathered in cloud data security.

How to choose invoicing software: a checklist

Pick invoicing software by answering these questions in order, not by brand:

1. How many invoices do you issue a month? At a handful, the free Ministry tools or a free plan are enough. At regular sales, the limit of three invoices at Fakturownia and iFirma stops being enough.
2. Who do you sell to? Invoices to consumers need not go to KSeF. For B2B sales the system is mandatory, and when you send a PDF outside KSeF you need a QR code.
3. Who keeps your books? If an accounting office does, an invoicing program the accountant can pull data from is enough. If you do it yourself, compare packages with self-service bookkeeping.
4. How fast do you want to see purchase invoices? KSeF sends no notifications, so how often the program fetches them is what counts.
5. What should the program connect to? A shop, a bank, a warehouse and a fiscal printer are typical reasons to move to a paid plan.
6. How many people will issue invoices? Fakturownia's free plan has one user, while the paid "Fakturowanie i CRM" package at wFirma has no user limit.

Invoicing software is usually the first paid or free tool a new business adopts, but rarely the only one. Once enquiries pick up and you need to remember who asked what, it's time for CRM for a small business. If you want incoming invoices to land automatically in your accounting system or a spreadsheet, see business process automation, which has a separate section on KSeF. The order of the rest of a new business's technology purchases — domain, mail, office suite — is in technology for a new business.