KSeF number checker widget
A small box that tells a visitor whether a KSeF number is well-formed: 35 characters, four segments, and a CRC-8 checksum that matches. KSeF is Poland's national e-invoicing system.
Preview
Code to copy
<iframe src="https://rowfa.dausystems.com/embed/ksef-number/" title="KSeF number checker" width="100%" height="230" style="border:0;max-width:560px" loading="lazy"></iframe>- The frame follows the visitor's light or dark setting.
- It needs no script on your page and no account.
- What the check covers is described on the KSeF number format page.
Questions
What does the widget cost?
Nothing. It can be placed on any site as it is, with the credit line it carries.
What does the widget send?
The number typed into it is checked in the visitor's browser and is not sent anywhere. Like every page of this site, the widget sends one anonymous visit event to our server, with the host name of the page that shows it. No cookies are set.
Is there a Polish version?
Yes. Use /embed/numer-ksef/ in place of /embed/ksef-number/ in the address.