In Slovakia, every cash register is an eKasa: it sends each receipt to the Financial Administration (Finančná správa) as it is issued, and the system gives the receipt a unique ID printed as text and as a QR code. Anyone can use that code to check the receipt against the authority's copy.
Checking with the Over doklad app
Install the Financial Administration's free Over doklad app for Android or iOS and scan the QR code on the receipt. The app shows the electronic version recorded in eKasa, so you can compare the store, the items and the total with the paper. The same check works on the Financial Administration's website without installing anything.
Without a QR code
On the website, type the receipt's ID. If it cannot be found, enter the details printed on the receipt instead: the business's verification code (OKP), the register code, the date and time, the receipt number and the total.
Reporting a suspicious receipt
If the receipt is not in the system or does not match, you can send it to the Financial Administration from the app, with when and where you got it and, ideally, a photo.
For a business
eKasa checks one receipt at a time; it does not give a company a list of the receipts its employees collected. A receipt shows the buyer's tax ID only when it was requested at the till.
Keeping the receipts
Thermal receipts fade. Photograph them in the Smartbills app and each one is kept with its items, every tax and the total, ready for an expense report.