Privacy
The short version: an address typed into a checker on this site does not leave your browser, and that is enforced by the browser, not only promised.
Addresses you type
Every check runs in JavaScript on your device. Pages with an address field are served with a Content-Security-Policy of connect-src 'none': the browser refuses every request a script on the page could make, so the address cannot be sent — not to this site and not to anyone else. It is not put in the URL, not stored in the browser and not logged. The same applies to lists in the batch check, to QR images and camera frames, and to the payment QR.
Those pages load no analytics and send no ad-view count. Banners still appear: an image is loaded, but that request carries nothing you typed.
Other pages
Pages without an address field (guides, reference tables, contact) may use Umami, a cookie-less statistics tool hosted by the operator, which counts page views without storing personal data and respects “Do Not Track”, and count banner views.
Contact form
A message sent through the contact form is stored so it can be answered and forwarded to the operator's inbox. The IP address is not stored; only a salted one-way hash of it is kept for a short time to limit spam.
Server logs
The web server handles ordinary page requests. Because no address is ever part of a request, no address can appear in them.
Contact
Crypto Address Checker · contact@cryptoaddresschecker.xyz