Since 1 April 2026, e-invoicing through KSeF (Poland's National e-Invoicing System) has been mandatory for essentially all VAT taxpayers. Large taxpayers joined on 1 February 2026. The smallest businesses, those under 10,000 PLN gross in monthly sales, have until 1 January 2027, which is also when administrative penalties under Article 106ni of the Polish VAT Act begin to apply. The legal basis is Dz.U. 2025 poz. 1203, and the Ministry of Finance maintains the official rollout schedule at ksef.podatki.gov.pl.
The practical consequence: a lot of companies picked the first tool that promised KSeF compliance. Now comes the harder question of whether that tool matches how they actually work.
I am the founder of Biurko.io, so treat the following with appropriate suspicion. That is why I start with where inFakt is simply the better choice.
Where inFakt wins outright
It is an accounting platform, not just invoicing. inFakt lets you stay on self-invoicing, move to self-service bookkeeping, or hand your filings to a dedicated accountant without changing systems. Biurko does none of that. No bookkeeping, no ZUS (social security) calculations, no JPK tax files. It issues invoices and talks to KSeF.
It is cheaper for a single entity. Per the inFakt price list (July 2026), the inFakt KSeF plan costs 0 PLN with unlimited KSeF sending, and inFakt Faktury costs 4.99 PLN net per month on an annual plan. Biurko's free tier caps KSeF sending at 10 invoices per month and its SOLO plan is 19 PLN net. For one sole proprietorship (JDG) issuing a dozen invoices a month, inFakt costs less. That is just true.
It is more mature. OCR on purchase invoices, mobile apps, bank integrations, phone support, years in market. Biurko is younger and I am not going to pretend otherwise.
If those three points describe your situation, close this article and stay with inFakt.
Where the "app plus accountant" model runs out
The friction starts when your work does not fit the shape of "one company, one owner, one accountant."
Real situations from user conversations:
You run an accounting firm (biuro rachunkowe) serving 40 clients. Each one means a separate account, separate login, separate KSeF integration.
Your group has a Polish subsidiary, a holding entity, and a dormant company. Three accounts, three subscriptions, three dashboards.
A client asks why an invoice did not go through, and your screen shows a raw KSeF error code with no context.
Your finance team in Poland works in Ukrainian, and the entire interface is in Polish.
None of these is a flaw in inFakt. They are simply a different job, and inFakt was not designed for that job.
What Biurko does differently
Many companies, one panel
Biurko was built from day one around one user holding many companies. You switch between entities without logging out, and roles are set per company: the bookkeeper sees documents only, the owner sees everything, a junior can draft invoices but not submit them.
The TEAM plan (49 PLN net/month) covers 5 companies and 5 users. SCALE (149 PLN net/month) removes both limits. For an accounting firm with 40 clients, that is one subscription instead of forty accounts.
Certificates, not tokens
Biurko authenticates to KSeF with a certificate. That was a deliberate architectural decision.
A KSeF token behaves like a password: whoever holds it can act on your behalf. A certificate is bound to a private key and a signature, and its expiry is visible in advance (Biurko notifies 30 days out).
The Ministry of Finance originally signalled that tokens would be retired at the end of 2026, but a June 2026 consultation proposed keeping them. The status is open, so do not treat any date as settled. Check the official announcements at ksef.podatki.gov.pl. Either way, a certificate is the safer default.
KSeF errors in plain language
KSeF rejects an invoice and returns a code. Say 21115. In the raw API that means an invalid certificate, and nothing more. You cannot tell whether the problem is yours or the gateway's.
Biurko translates codes into sentences a human can act on: the buyer's NIP (Polish tax ID) failed validation, check for a PL prefix; or the session expired before submission and the invoice is queued for retry. This sounds trivial until you are the one answering a client at 5 p.m. on a Friday.
Offline24, emergency mode, and UPO
When KSeF is unavailable, invoices must be issued offline with a verification code and QR, then submitted afterwards. The statute requires submission by the next business day (offline24 mode) and within 7 business days of the end of a declared outage (emergency mode). Biurko generates the offline code, prints the QR on the PDF, and tracks the submission deadline. It also retrieves the UPO (the official confirmation receipt) and verifies the Ministry of Finance signature automatically.
A Ukrainian interface
The full panel runs in Ukrainian, not "translated menus, Polish everywhere else." That matters for roughly 60,000 Ukrainian-owned businesses operating in Poland and for the accounting firms serving them. I do not know another Polish KSeF system that offers it.
Pricing side by side
inFakt Biurko.io Free plan inFakt KSeF, 0 PLN, unlimited sending FREE, 0 PLN, 10 KSeF submissions/month Cheapest paid inFakt Faktury, 4.99 PLN net/month SOLO, 19 PLN net/month Multiple companies separate accounts TEAM: 5 companies, 49 PLN net; SCALE: unlimited, 149 PLN net Bookkeeping yes, up to a dedicated accountant no Ukrainian UI no yes KSeF auth Profil Zaufany, certificate, token certificate
Net prices, July 2026. Price lists change. Verify with both vendors before deciding.
Three scenarios
One Polish entity, a handful of invoices, lowest cost wins. Choose inFakt.
One entity, but you also want an accountant inside the same system. Choose inFakt. Biurko does not offer that.
An accounting firm, a group of entities, or a Ukrainian-speaking team. Choose Biurko. This is where the multi-company panel, per-company roles, certificate auth and readable errors stop being nice-to-haves.
Checklist before you switch
Count the entities you actually handle. One versus more than one changes the entire decision.
Check how your current tool authenticates to KSeF: token or certificate.
Confirm it supports offline24 and emergency mode, not just online submission.
Confirm it retrieves and verifies the UPO, rather than merely displaying it.
Map who on your team needs access and to what. More than one person means you need roles.
Export your contractor and invoice data before migrating. Always.
Send one test invoice through the KSeF test environment before switching production.
Bottom line
inFakt and Biurko are not competing for the same customer, even though both list KSeF on the box. inFakt is an accounting ecosystem for a single business. Biurko is a KSeF tool for someone handling several businesses who needs control over authentication, deadlines and error handling.
If that second description is you, create a free account at biurko.io and connect your first company. The FREE plan is enough to test the full cycle: issue, submit, retrieve the UPO. No card required.
FAQ
Is Biurko.io cheaper than inFakt? Not in the basic case. For a single sole proprietorship, inFakt offers a free KSeF plan with unlimited sending and a paid tier at 4.99 PLN net. Biurko becomes cheaper once you handle several companies, where one TEAM or SCALE plan replaces multiple separate accounts.
Does Biurko handle bookkeeping? No. Biurko issues invoices, submits them to KSeF, imports incoming purchase invoices and manages UPO receipts. Tax filings stay with your accountant or accounting firm.
Can I migrate my data from inFakt to Biurko? Yes. Export contractors and invoices to file, and note that your incoming invoice history already lives in KSeF, from which Biurko imports documents automatically.
What is the difference between certificate and token authentication in KSeF? A token works like a password: anyone holding it can act as you. A certificate relies on a private key and signature, carries an expiry date and is harder to leak unnoticed. For the current status of tokens, check ksef.podatki.gov.pl.
When do penalties for missing KSeF invoices start? Administrative penalties under Article 106ni of the VAT Act apply from 1 January 2027. A transition period runs through the end of 2026, but the obligation to issue invoices via KSeF already began on 1 February and 1 April 2026, depending on company size.