In short: we collect almost nothing. This version took effect on 1 November 2026.
The illusions run on your screen
Every illusion is drawn by your browser. Your slider settings, your score on the "how strongly are you fooled?" test and any share card you make are created on your device and not sent to us. A few settings are remembered in your browser so the page opens where you left it; clearing your browser data removes them.
Server records
Like any web server, ours writes a short log entry for each request (IP address, date, page). These logs are for security and are deleted on a rolling basis.
Cookies and advertising
There are no tracking cookies of ours. Should we ever show ads or measure traffic with an outside service, that provider may use cookies, and we will update this page first.
Messages to hello@illusionsblog.com are read by a person and kept only as long as the conversation needs. We never sell reader details.
Young readers
Kids are welcome to play with the illusions, but we do not ask for any personal information, and we do not knowingly hold any from children under 13. A parent who thinks we have some can ask us to delete it.