Privacy

Short version: your scrolling never leaves your device. There is no backend, no database, and no login. Wheel events, saved runs, labels, and imported reports are never sent anywhere.

Stored only in your browser

• Theme choice (only if you pick Light or Dark explicitly) and language preference — via local storage.
• Saved runs (Run A / Run B), an optional last-run summary, and exported reports you choose to download — via local storage and files you save yourself.

Clearing site data in your browser removes all of it.

Aggregate usage measurement

Pages on this site load Google Analytics 4 (provider: Google LLC) to count page views and a small set of aggregate interface events: test starts and completions, completed Run A / Run B comparisons, report exports, and theme or language changes. These events carry no wheel-event data, no run labels, no report contents, and no personal information. Google's handling of that data is described in Google's Privacy Policy.

You can block the measurement script with any tracker blocker — the scroll test itself runs entirely locally and works fully without it.

What else this page contains

Apart from the analytics script described above, this site ships no advertising scripts and no other third-party trackers. If that ever changes (for example, if hosting-level analytics or a contact mailbox is added), this page will name the provider, the purpose, and the retention before it takes effect.