What a SEPA QR code contains
Twelve short lines in a fixed order: the service tag BCD, version 002, the character set (1 = UTF-8), SCT for SEPA credit transfer, the BIC (optional since version 002 within the EEA, required for Switzerland, the UK and the other SEPA countries outside it), the beneficiary name (70 characters), the IBAN, the amount in euros (EUR12.50), a purpose code, then either a structured RF reference or a free text of 140 characters, and a note to the payer. 331 bytes at most.
Checked before you print
A wrong IBAN on a printed code means lost payments. The tool checks the IBAN the way banks do (ISO 13616: country, length and the two check digits, which catch typos and swapped digits), the BIC format, the RF reference (ISO 11649), the amount range and the size limit, and tells you which field to fix.
Where payment QR codes help
Invoices and quotes, rent and shared expenses, associations and donation boxes, markets and craft fairs, deliveries paid on arrival, tips. Print the IBAN in clear next to a SEPA code, and a short line such as “Scan with your banking app” so people know what to do.