What this site collects: nothing
There are no accounts and no sign-in, no analytics, no advertising, no tracking pixels and no cookies set by the site. It does not know who you are or what you answered.
What stays in your browser
Your progress, your settings (theme, timer, filters), custom and AI-generated drills, and wiring sandbox drafts are kept in your browser's local storage, on your device. They never leave it unless you export them yourself.
You can delete them on the Stats and Contribute pages, or by clearing this site's data in your browser. They are then gone for good.
AI mode and your API key
If you use AI mode, you paste your own Anthropic API key. It is stored only in your browser and sent only to Anthropic's API (api.anthropic.com), directly from your browser, when you generate or analyze a drill. This site never receives it, and you can remove it on the AI mode page at any time.
What you send to Anthropic is covered by Anthropic's privacy policy.
Hosting
The site is delivered by Cloudflare. Like any web host, Cloudflare receives the technical details of each request (your IP address, browser type and the page requested) to serve the page and protect its network, under Cloudflare's privacy policy. This site does not use that data.
Links
Links to official code and government sites, and to Anthropic, lead to sites with their own privacy practices.
Children
The site is for people learning a trade and is not directed at children under 13.
Changes
If any of this changes, for example if analytics are ever added, this page and its date will say so first.