Invoice fraud checker for small businessesCatch fake bank details before you pay them

It checks each supplier invoice against the bank details you confirmed, and says Stop before the money moves.

For Windows 10 and 11. From £129 a year, the same price every year. It reduces the risk of paying a fraudster and does not replace your own checks.

An example, from an invented supplier

From: Pellowmere Supplies
Subject: Invoice 4471, new bank details

“Please note our bank details have changed. Please pay invoice 4471 to the new account.”

Stop: do not pay this yet.

The invoice asks for sort code 20-00-00, account ending 7701. You confirmed 12-34-56, ending 5432 for Pellowmere Supplies. Call them on a number you already have.

Bank details changed
Email asks to change bank details
Sender failed its own checks

The invoice, beside your register

Pellowmere Supplies is an invented supplier. Pick a case to watch the checker put the bank details on the invoice beside the ones you confirmed.

Details changed

On the invoice

Invoice 4471 from Pellowmere Supplies

£2,340.00

Supplier: Pellowmere Supplies Same
Sort code: 20-00-00 Different
Account: ending 7701 Different

In your register

Pellowmere Supplies, trusted

Confirmed by phone on 3 March, on a number you already had.

Supplier: Pellowmere Supplies
Sort code: 12-34-56
Account: ending 5432

Stop: do not pay this yet. Call the supplier on a phone number you already have, not one from this email or invoice, and confirm the bank details before paying.

Details match

On the invoice

Invoice 4471 from Pellowmere Supplies

£2,340.00

Supplier: Pellowmere Supplies Same
Sort code: 12-34-56 Same
Account: ending 5432 Same

In your register

Pellowmere Supplies, trusted

Confirmed by phone on 3 March, on a number you already had.

Supplier: Pellowmere Supplies
Sort code: 12-34-56
Account: ending 5432

Nothing unusual. The details match the ones you confirmed. Automated checks can be wrong, so keep your normal payment checks too.

An example, with invented details. The program shows bank details this way: a sort code and the last four digits of an account.

£1.28 billion was lost to payment fraud in the UK in 2025, up 4 per cent on 2024.

£576.4 millionof it was authorised push payment fraud: money somebody was persuaded to send, up 19 per cent on 2024.
£75.6 millionof that left business accounts rather than personal ones, down 11 per cent on 2024.

Some of that money left because somebody believed an email.

Figures for 2025 from the UK Finance Annual Fraud Report 2026.

The scale of the problem, in figures

Every check ends in one of four answers.

Each comes with the reason in plain English and what to do next.

Stop

Do not pay until you have called the supplier on a number you already have and confirmed the bank details.

Changed bank details
Another supplier's bank details
Two sets of details in one invoice
A request to change bank details
An email that failed its sender's own checks
A lookalike sender

Check

Look at something first.

A new supplier
Details nobody has confirmed yet
Replies going somewhere else
Pressure to pay today
An unusual amount
An invoice made differently from usual
Details that fail the UK banks' own sort code check

Nothing unusual

The details match the ones you confirmed. Automated checks can be wrong, so keep your normal payment checks too. It does not mean safe.

No bank details to check

The invoice gives no bank details, so there is nothing to compare with your register.

How it checks an invoice before you pay it

The same four steps, in this order.

It collects your invoices for you.
Turn on automatic checking and it reads new invoices from your email by itself while it is open, on a schedule you choose from every 15 minutes to every 4 hours, hourly unless you change it. Close it and the checking waits until you open it again. You can drop in one you have downloaded, and Pro can watch a folder too. Emails with no invoice attached are read too when they come from a supplier or talk about payment, because fraud often starts with one asking you to update a supplier's bank details.
It looks at the email the invoice came in.
Whether it failed its sender's own checks, came from an address made to look like a supplier's, asks for replies to go somewhere else, or says the bank details have changed.
It checks the bank details.
The sort code and account number on the invoice are compared with the ones you confirmed for that supplier, and with every other supplier's in your list.
It says Stop before you pay.
The answer shows the details the invoice asks for beside the ones you trust, and Windows shows a notification when a run finds an invoice to stop.

One price a year, the same every year

Pay once a year. Every update is included while your licence is paid for, and you can cancel at any time.

What each plan includes
Who it suits and what it covers
	Personal£129 a yearUp to 2 devices, with up to 5 clients kept apart.Buy Personal	Pro£399 a yearUp to 10 devices, with up to 15 clients kept apart.Buy Pro	Pro+£799 a yearUp to 30 devices, with up to 30 clients kept apart.Buy Pro+
Who it is for	The typing saved, and the warning before you pay. For sole traders, small businesses that pay their own suppliers, and bookkeepers with a few clients.	Control over who can change where the money goes. For businesses with more than one person paying suppliers, and bookkeeping practices. One price for the whole business.	Pro for more devices and more clients. For larger firms, groups of companies and busier practices. One price for the whole firm.
Clients kept apart, each with its own register, audit log and exports	5	15	30
Devices it can be activated on	2	10	30
Inboxes	1	Any number	Any number
In every plan
Each invoice checked against the bank details you trust, with the email it came in, and a Windows notification when a run finds one to stop	Included	Included	Included
As many suppliers as you have, in a register with their bank details encrypted and an audit log, with unlimited pages and templates of your own	Included	Included	Included
Bank statements with every balance checked, and exports to CSV and to a new Google spreadsheet, and import files for Xero, QuickBooks and FreeAgent	Included	Included	Included
Added by Pro and Pro+
Payment runs checked against the register before they go to the bank, and a second person's approval before new bank details are trusted	Not included	Included	Included
A shared register in MySQL or PostgreSQL, whole folders of PDFs, and watched folders	Not included	Included	Included
Statements joined across months and accounts, and transactions categorised by rules you edit	Not included	Included	Included

Try it first. The free trial runs for 14 days or 20 pages of your own PDFs, whichever comes first, for one client and up to 5 suppliers, with CSV export. Google Sheets, the files for Xero, QuickBooks and FreeAgent, your own templates and more than one client come with a licence. No card and no account.

Download the free trial

Renews yearly. You can cancel at any time. Every renewal reminder tells you how.

If you stop paying, the checks stop. If it is not renewed within 30 days of the day it is paid until, nothing new is collected, checked or read until you renew, and everything already in the program stays there to look at and export.

Each computer it is activated on counts as one device. If a licence is on more than it covers, the program says so, and everything goes on working.

More than 30 clients or 30 devices? Tell us what you need and we will agree something that fits.

Invoice Fraud Checker reduces the risk of paying a fraudster. It cannot guarantee that any payment is safe, and it does not replace your own checks: always confirm new or changed bank details with the supplier on a phone number you already have.

A register of who you pay, and where

The register is built from the invoices you already have. Bank details are trusted only once someone confirms them with the supplier and records how, when and by whom.

Three suppliers in a register
Supplier and bank details	Status	How they were confirmed
Pellowmere Suppliessort code 12-34-56, account ending 5432	Trusted	Confirmed by a phone call to a number already held on 3 March 2026, by the office manager.
Hartley Joinery Ltdsort code 30-94-57, account ending 2210	Waiting for approval	Confirmed in person on 6 October 2026, by the bookkeeper. Waiting for a second person to approve them, which comes with Pro.
Birch Cleaning Servicessort code 20-45-77, account ending 0918	Seen, not confirmed	Read from invoice 1882. Nobody has confirmed these with the supplier yet, so its invoices say Check.

Built from your invoices.

Build from invoices reads the bank details on the invoices you have collected and puts them under each supplier as seen, not trusted, ready for you to confirm with a phone call.

Every change on the record.

An audit log keeps every change to the register and every decision about an alert. Each entry is sealed to the one before it, so a change made behind the tool's back shows.

Clients kept apart.

Each client has its own suppliers, bank details, audit log and register key. Bank details are only ever compared within one client, so a payment for one client is never checked against another client's suppliers.

A second pair of eyes, with Pro and Pro+.

Newly trusted bank details wait until an approver other than the person who confirmed them approves them. The payment run file for your bank is checked against the register before you send it, and a run with a payment to stop says so.

It types up every invoice it checks

Invoices

The same reading that finds the bank details takes the invoice number, date and total from each invoice. Anything it is unsure of waits for you, beside the page it came from, rather than being exported as if it were right.

Bank statements

Every transaction on a statement, with the statement's balances checked before a single row is exported.

Barclays, HSBC, Lloyds, NatWest, Santander, Nationwide, Monzo and Starling have templates of their own. Statements from other banks are read too, and always sent for you to check.

It exports to CSV and to Google Sheets, and makes import files for Xero, QuickBooks and FreeAgent.

What it cannot do

It reduces the risk of paying a fraudster. It cannot guarantee that a payment is safe, and it does not replace your own checks.

It knows the suppliers you tell it about. An invoice from a supplier not in your register yet, or with details nobody has confirmed, gets Check rather than Nothing unusual.

These checks are automated, and automated checks can be wrong both ways. The checker may warn you about an invoice that is genuine, and it may not warn you about one that is fraudulent. A fraudster who already has the right details can produce an invoice that matches.

Confirming a change of bank details with the supplier, on a number you already hold, is the strongest check there is.

It is for Windows only. It needs a 64-bit Windows 10 or 11 computer. There is no Mac version.

Your suppliers' bank details stay on your computer

It runs on your own computer, and your list of suppliers and their bank details stay there, unless you choose to keep them in your own database server with Pro. There is no account to make and no server of ours your invoices pass through. Below is everything that does leave, and when.

Stays on your computer

Your register of suppliers, with their bank details encrypted with a key kept in Windows' own password store, and shown in full only when you ask. With Pro you can keep it in your own database server instead.
Every invoice and statement, and what the checks found in each one. Neither the files nor the figures read from them are encrypted, so keep any copy of the program's folder somewhere as private as your email.
The checks on each email. They are made here, and only what they found is kept, never the message.
Each PDF, read in a separate, limited process. Nothing inside one is ever run.

Leaves it, and only then

Your mail serverWhenever it collects mailRead over an encrypted connection. Nothing is deleted or moved.
Microsoft's sign-inOnly if your inbox signs in with MicrosoftThe sign-in itself, so no app password is needed.
GoogleOnly if you connect itThe rows you export, into spreadsheets the program created and no others.
Your own database serverOnly if you choose one, with ProThe register and everything the program keeps, held there instead of on this computer, so your team can share it.
AnthropicOnly if you turn on AI extraction, with your own keyThe text of documents the templates could not read, with the sort code, account number and IBAN the program recognises taken out first. The bank's BIC and the name on the account still go, and so does a bank detail it cannot recognise. Never a PDF, an email or a bank statement.
JatzoWhen you activate or remove a licenceYour licence number and a random install ID, to count devices. If our site cannot be reached, it activates all the same. If you turn on update checks, it asks which version is the latest. Never your documents, your suppliers or their bank details.

Before you buy

The questions people ask first.

Does it stop all invoice fraud?

No tool can. It checks the things invoice fraud nearly always changes, the bank details and the email they arrive in, and tells you to stop and call the supplier when they do not match what you confirmed. Keep your own payment checks as well.

How does it know which bank details are right?

From you. It builds a register of your suppliers from the invoices you already have, and each set of bank details is trusted only once someone confirms it with the supplier, on a phone number you already hold, and records how, when and by whom. Until then, an invoice using those details says Check.

Do my suppliers' bank details leave my computer?

Not from the register. It is kept on your computer, with its bank details encrypted, or in your own database server if you choose one with Pro, and nothing from it is ever sent to Jatzo. AI extraction goes further, and only if you switch it on with your own Anthropic key. When the templates cannot read a document fully, the text read from it goes to Anthropic so the missing values can be suggested. The sort code, account number and IBAN the program recognises are taken out first. The bank's BIC, the name on the account and any bank detail it cannot recognise go as printed. Bank statements are never sent, and AI extraction is off until you turn it on.

Does it send anything to Jatzo?

Only your licence usage. When you activate a licence or a renewal key, it sends your licence number and a random ID made on that computer, so we can count the devices your licence is used on. Removing a licence sends the same two things again, so that computer is no longer counted. It never sends your documents, your suppliers or their bank details, your name or email address, or anything about the computer. Apart from that it sends nothing, unless you switch on update checks: then it asks this site whether a newer version is out, and the question carries no licence, version or name. If a licence is on more computers than it covers, the program tells you, and everything goes on working.

Can a bookkeeper keep each client's suppliers apart?

Yes, with every licence. Personal keeps up to 5 clients apart in one install, Pro 15 and Pro+ 30, each with its own suppliers, bank details, audit log, inboxes, exports and register key. Bank details are only ever compared within one client, so a payment for one client is never checked against another client's suppliers. The client in use is named on every screen, and switching takes one click. For more than 30 clients, tell us how many and we will agree a licence that covers them.

What if my computer breaks?

The register's key lives in this computer's password store, so save a copy of it, under a passphrase, from the Suppliers screen, and keep the file somewhere safe. The same copy puts the register on a new computer.

What do I need?

A Windows 10 or 11 computer, and an email account it can read. Microsoft 365, Outlook.com and Hotmail sign in with Microsoft. Gmail, Yahoo Mail, iCloud Mail and most others connect with an app password, made in their security settings. A work Microsoft 365 account may need its administrator to approve the program the first time it signs in. Invoices and statements you download can be checked and read without an email account.

Will Windows warn me when I install it?

Possibly, for now. Windows says "Windows protected your PC" about programs it has not seen many times before, and the installer's signature is new. Choose More info and check that the publisher it names is Jatzo Ltd, then choose Run anyway. If it names anyone else, or no publisher, do not run it and tell us. It installs for you alone, with no administrator password, and is in your Start menu.

To check the file before you open it, right-click it, choose Properties, then Digital Signatures. It should list Jatzo Ltd. You can also check its fingerprint, its SHA-256 hash, to be sure it is the exact file we published. Open PowerShell in the folder you downloaded to and run Get-FileHash Jatzo-Invoice-Fraud-Checker-Setup-0.4.0.exe. It should print c423caca07bfa2ec59c2180cf7ebaef2af922f03127c647f8c0da61a810b6b5d. If it prints anything else, do not run it and tell us.

What happens if I stop paying?

If it is not renewed within 30 days of the day it is paid until, nothing new is collected, checked or read until you renew, and everything already in the program stays there to look at and export. Nothing is deleted: your register of suppliers, everything the program found and the register's key stay on your computer, and you can still open it to look at them, export them and save the key. What stops is new work: no mail is collected and no invoice or payment run is checked until you renew. The date is written into the licence key itself rather than checked against us, and every renewal email says when it is. You can cancel from the link in every renewal email, and if you come back later you pay the same yearly price and carry on from where you stopped.

Can I get a refund?

Not for changing your mind once your licence has started. The licence key is checked on your own computer and nothing we do can switch it off, so once your key is issued we cannot take the program back. At checkout you are asked to start straight away and to give up the 14-day right to cancel that a download would otherwise carry; until it starts, you can cancel for any reason and be refunded in full. The free trial is there to find out first: it runs for 14 days or 20 pages, whichever comes first, and keeps up to 5 suppliers, which is enough to put your own invoices and your own bank statements through it and see what it says about your own suppliers. If the program is faulty, or does not do what this page says it does, that is a different thing entirely and we will put it right or refund you.

How do I get my licence?

Your licence key is emailed to you after you pay. Paste it into Settings in the app and choose Activate.

Does it use AI?

Only if you turn it on, to read invoices its templates cannot. It uses your own Anthropic API key, so the cost is on your Anthropic account. The text of those invoices goes to Anthropic, with the sort code, account number and IBAN the program recognises taken out first, and the app says so before you agree. The checks on bank details and emails never use AI.

Is there a Mac version?

No. The download is for Windows.

Try it on your own invoices first

The free trial runs for 14 days or 20 pages, whichever comes first, for one client and up to 5 suppliers, with CSV export. No card and no account. Check a few of your own invoices, read one of your own statements, and see what it says before you decide anything.