Start
When you issue up to 10 invoices a month
0 PLN forever
Start free- Unlimited KSeF invoices: purchases and sales
- Issue up to 10 sales invoices a month
- Mark what is already paid
From 1 January 2027, KSeF covers even the smallest companies, and mistakes can be fined.
KSeF invoices, payments, finance, taxes and HR in one place.
More than KSeF. The finance team your company doesn't have, working alongside the accountant you already do.
Księguś is the finance toolbox for small businesses and accounting offices in Poland. Start free, and your accountant joins at no cost.
- No card needed
- Nothing is charged automatically
- Cancel any time
Already have an account? Sign in
From invoice to settled payment
This is what a month with Księguś looks like. You can switch each step on or skip it.
Invoices arrive on their own
We fetch purchase and sales invoices from KSeF. Invoices from outside KSeF you forward by e-mail or upload as a PDF or photo.
You approve on your phone optional
When someone else makes the payments for you, such as your bookkeeper or an employee, you just approve invoices on your phone and save time. You see the due date, the amount and anything missing. Paying yourself? Skip this step.
You pay with one file
You tick the invoices and Księguś prepares a payment file to upload in your bank. Every transfer carries the invoice's KSeF number in its title, as the law requires from 2027. We check each account against the VAT white list.
The statement reconciles itself
You upload your bank statement and the transactions match themselves to invoices. Only a few are left for you to confirm.
What Księguś can really do
Fetching invoices from KSeF is just the start. Księguś does the work a finance team would do in a bigger company, and these are the things that save the most time and hassle.
Reads photos of invoices and receipts
Take a photo or upload a PDF and Księguś reads the NIP, amounts, due dates and account number. You just check them.
Checks before you pay
We check the supplier's account against the VAT white list, and you see missing details before the bank rejects the transfer.
Works out the exchange rate
For an invoice in euros or dollars it fetches the NBP rate for the right day and converts the VAT to złoty.
Pays from the right account
Invoices in złoty go into a file for your złoty account, and invoices in euros into a SEPA transfer from your euro account.
A correction in a few clicks
Cancel an invoice or lower a price, and Księguś prepares the correction invoice to send to KSeF.
Works out the payroll
From the contract and hours worked it calculates ZUS, the PIT advance and take-home pay, and the wages go into one transfer file.
The app is made of modules. Each company switches on only the ones it needs and can change that at any time.
Invoices from KSeF always on
Purchase and sales invoices fetched from KSeF, approval, marking as paid, and corrections shown next to the invoice they change.
Issuing invoices
VAT invoices and pro formas sent to KSeF. Buyer details filled in from the VAT white list by NIP, a second language on the PDF, and sending by e-mail.
Invoices outside KSeF
Each company has its own address to forward invoices to. We read PDFs and photos automatically, and a person always checks them before payment.
Payments
A payment file (.pli or .txt) to upload in your bank, separately for each company account. Księguś never sends money on its own.
Bank statement
MT940 from any bank and CSV from several popular ones. Transactions match to invoices, and month by month you see what is settled.
Vendors and customers
Suppliers and customers in one place, with expense categories and invoice history.
Finance and taxes
Income and expenses month by month, a comparison with last year, and an estimate of VAT and the CIT advance with their due dates.
HR
Employment contracts, mandate and task contracts, documents, shift schedule, working hours, leave and sick notes. Everyone sees only their own.
For the accountant
A monthly summary in Excel or CSV: invoices, VAT, payments and transfers, together with the bank statements.
Why Księguś
Księguś is not accounting software. It takes care of what happens in the company before the documents reach the accountant.
Take only what you use
Just invoices, invoices with payments, or the whole set with HR. A switched-off module disappears from the menu and its data stays.
Alongside your accountant
An accounting office sees all its client companies on one dashboard: what waits for approval, what is overdue, and where a statement is not reconciled.
Everyone sees only their part
Permissions follow the role in each company: running the business, accounting, read-only, managing shifts or working in the team. Team members never see invoices or amounts.
Mobile friendly
Approvals, the schedule and documents work comfortably on a phone. You only need a desk for statements and reports.
In each person's language
The app and its e-mails are in Polish, English, German and Ukrainian. Everyone picks their own language, and the invoice in KSeF is always in Polish.
Your money stays in your bank
We never ask for access to your account. You upload the payment file yourself, and we keep your data on a server in the EU with an encrypted copy every night in Poland. You can protect your sign-in with a code from your phone (2FA).
See how it looks
Real screens from the app with sample data: a bakery, a car repair shop, a hair salon and the accounting office that serves them. They are shown in Polish; the app works the same in English, German and Ukrainian.
How do you see yourself using Księguś? Pick what fits you best.
Jan runs a bakery
Piekarnia Kłos, invoice approval switched on
- In the morning he goes through new KSeF invoices on his phone and approves them with one tap.
- He ticks what to pay and downloads the payment file for his bank.
- Before paying he sees whether the supplier's account is on the VAT white list and whether the bank will be missing anything.
- In the Overview he checks income, expenses and upcoming taxes.
Anna runs an accounting office
Biuro Rachunkowe Bilans, three client companies
- On the office dashboard she sees every company and what needs attention in each.
- She uploads a company's statement and most transactions match to invoices on their own.
- At month end she downloads the summary, without chasing anyone for paperwork.
Ola plans the salon's shifts
Studio Fryzur Ola, a team of four
- She sees the whole month, a week per row, with hour totals and public holidays.
- Leave and sick notes show up in the schedule straight away.
- Everyone in the team has their schedule, contract, leave balance and documents on their phone, and enters their own hours.
Ola starts by choosing
Studio Fryzur Ola, a new company
- At her first sign-in she picks a ready-made set or her own modules.
- Invoices from KSeF are always on; she adds the rest when she needs it.
- A switched-off module disappears from the menu, and its data stays in case she wants it back.
The best test is your own invoices. You open a trial account yourself, no card needed. Prefer sample data first? Write to us and we will set up a demo account for you.
Choose your plan
Every new account gets the full PRO plan free for 30 days. After that you pay only for what you use, or stay on the free Start plan.
Issue 10 invoices a month or fewer? The Start plan is enough and free forever, and KSeF invoices come in without limit.
Your accountant uses it for free. You invite them by e-mail and they get their own account, on every plan, including the free Start. You pay per company, not per person, so neither your accountant nor their accounting office pays anything.
Companies with an accounting office pay 20% less. If your office looks after at least 3 companies in Księguś, the discount applies automatically on every paid plan.
Invoices
When you issue more, or get invoices outside KSeF
35350 PLN net / monthnet / year
Try it free- Everything in Start
- KSeF overview: overdue invoices and those due in 7 days, money in and out by month
- Unlimited invoice issuing
- Invoices from outside KSeF: e-mail, PDF and photos
Recommended
Entrepreneur
When you pay suppliers and want a reconciled statement
95950 PLN net / monthnet / year
Try it free- Everything in Invoices
- Dashboard with your bank statement: what is settled, what to confirm and what is unmatched
- Payment file for your bank
- Bank statement matched to invoices
- Suppliers, customers and expense categories
PRO
When you also want finances and your team
1751750 PLN net / monthnet / year
Try it free- Everything in Entrepreneur
- Finances and taxes: VAT and CIT advances
- Staff: contracts, rota, leave and sick leave
Prices are per company, net of Polish VAT, which is added. You pay by bank transfer, monthly or yearly. You can change your plan at any time.
Do you run an accounting office?
Open an office account, free of charge. You work for all your clients from one dashboard, add their companies yourself and invite colleagues, with no fee per person. Each new company gets 30 days of the PRO plan, then pays for its own plan or stays on the free Start plan, and from 3 companies in your office each pays 20% less.
We switch the office account on once GUS confirms accounting activity (PKD 69.20.Z). If GUS shows something else, we check by hand, usually within one working day.
How to start
- Sign up. Your name, e-mail, company name and NIP.
- Click the link in the e-mail. You get 30 days of PRO right away.
- Paste your KSeF token. Invoices come in on their own. How to get the token
Who it is for
Small businesses
For businesses that pay their own invoices and want to stay on top of due dates, while a bookkeeper or accounting office keeps the books.
- from sole traders to limited companies with a dozen or more staff
- shops, workshops, restaurants, cafés and services
- several business bank accounts, including in euro
Accounting offices
For offices that want their clients' invoices and statements right away, not in the last week of the month.
- all client companies on one dashboard
- separate roles for accounting and read-only access
- the monthly summary ready to download
- a free account for the office, and its client companies pay 20% less
Questions
Does it replace accounting software or my accounting office?
No. Księguś keeps invoices, payments and statements in order, and your accounting gets a ready summary from it. The books, tax returns and ZUS stay where they were.
Does Księguś have access to my bank account?
No. It prepares a payment file that you upload in online banking, and reads statements downloaded from your bank. It never sends money.
Where is my data?
Your data never leaves the European Union. The app runs on our server in Finland, and every night we make an encrypted backup with a different provider, in Warsaw. We never sell your data or use it for advertising.
How much does it cost?
From PLN 0. If you issue up to 10 invoices a month, the Start plan is free forever and KSeF invoices come in without limit. Unlimited issuing in Invoices costs PLN 35, Entrepreneur PLN 95 and PRO PLN 175 a month, net. Pay for a year and you get 2 months free. See pricing.
What happens after the 30 free days?
Nothing is charged automatically, because you never give a card. If you choose a paid plan, you get a pro forma invoice to pay by bank transfer. If you choose nothing, the company moves to the free Start plan. No data is deleted, and modules outside Start come back once the plan is paid.
How does Księguś connect to KSeF?
Through the official API of the Polish Ministry of Finance, using your KSeF token. There is nothing to install and no invoices to retype. You paste the token once in the company settings, and invoices come in on their own. See how to get the token.
Does the accounting office pay for Księguś?
No. The company pays for its own plan. Accountants and accounting offices have a free account, and when an office looks after at least 3 companies in Księguś, each of them pays 20% less.
When does my company have to use KSeF?
Most companies have issued invoices in KSeF since 2026. The smallest ones, with sales up to PLN 10,000 a month, may issue outside KSeF until the end of 2026. From 1 January 2027 KSeF applies to everyone, and mistakes can be fined. Your suppliers already send invoices to KSeF, so Księguś can fetch them right away. How to get ready.
Do I have to put the KSeF number in the transfer title?
Yes, from 1 January 2027. When you pay another active VAT payer by bank transfer for a KSeF invoice, the title must carry its KSeF number. For several invoices from the same seller paid in one transfer, you use a collective identifier from KSeF. Księguś does this for you: every transfer in the file already has the right number in its title. Card, BLIK and cash payments are not covered.
Which banks does Księguś work with?
Most Polish banks accept the payment file (.pli). We read statements in MT940 from any bank that offers it, and in CSV from PKO BP, Erste (formerly Santander), Nest Bank and Revolut.
See Księguś in your company
Sign up and use everything free for 30 days, no card needed. Questions, or do you run an accounting office? Write to kontakt@twojksiegus.pl.