Privacy Policy

Last updated: November 13, 2026

StemDriller (stemdriller.com) is a free website for students to practice problems. This policy explains what information is and isn’t collected when you use it.

What we store, and where

StemDriller has no accounts and nothing to sign up for. Your timer, stats, practice history, favorites, theme, and settings are saved only in your browser’s local storage. They stay on your device and are never sent to us. Clearing your browser data erases them.

What we don’t collect

We don’t ask for your name, email, or any personal details to use the site, and we don’t use analytics or tracking tools of our own.

Advertising

StemDriller may show ads provided by Google AdSense. Google and its advertising partners use cookies and similar technologies to show ads based on your visits to this and other websites.

You can opt out of personalized advertising at Google Ads Settings (https://adssettings.google.com), or at aboutads.info (https://www.aboutads.info) for some other vendors. You can learn how Google uses data from sites that use its services at https://policies.google.com/technologies/partner-sites.

If you are in the European Economic Area, the United Kingdom, or Switzerland, you will be asked for your consent before personalized ads are shown. If you decline, you may still see ads that aren’t personalized, which don’t use your browsing history.

Cookies

StemDriller doesn’t set cookies of its own. Cookies may come from our advertising partners (described above) and from our hosting provider for security purposes. You can control or delete cookies in your browser settings.

Fonts

The site loads a font from Google Fonts. When it does, your browser connects to Google’s servers, which receive your IP address and browser information. See Google’s Privacy Policy (https://policies.google.com/privacy).

Hosting and server logs

The site is hosted by Cloudflare. Like most hosts, Cloudflare may log technical information such as IP address, browser type, and pages requested, for security and operation of the service.

Contacting us

If you email us at [email protected], we receive your email address and whatever you write. We use it only to reply and to fix reported mistakes, and we don’t sell or share it.

Children’s privacy

StemDriller is not directed at children under 13, and we don’t knowingly collect personal information from them.

Educational content disclaimer

Practice problems and solutions may contain errors and are not a substitute for instruction. If something doesn’t make sense, check it against a textbook, teacher, tutor, or other trusted source.

Changes to this policy

If we make changes (for example, adding accounts or analytics), we’ll update this page and the date above.

Contact

Questions about this policy: [email protected]