Privacy
No account, no tracker, no resource loaded from a third party.
What is kept
No account exists, no sign-up is offered, no personal data is asked for.
The web server keeps a standard access log — IP address, date, URL requested, browser — as every server does. It serves technical diagnostics and nothing else.
Analysis results are cached for five minutes, then erased. A per-IP counter is kept for one hour, for the request cap.
Header analyser
The text pasted into that tool never leaves your browser: the analysis is done by local JavaScript, with no call to the server. You can verify it in your browser's network tab — you will see no request at the moment of analysis.
Third-party services
No font, script or image is loaded from another domain. The site's content security policy forbids it technically.
Analysing a domain does, however, make the server query public DNS resolvers, the relevant registry's RDAP, and the site itself. Those requests come from the server, never from your browser: your IP address is not passed on to them.
Cookies
One only, optional, to remember the chosen language. The light or dark theme is kept in the browser's local storage and never leaves your machine. No analytics cookie.