Privacy

Last updated 12 October 2026.

Without an account

Your finished lessons are saved in your own browser (localStorage). Nothing about them is sent to us.

If you join the email list

We store your email address and where you signed up, and use it only to tell you about new modules and course news. Every email has a way to unsubscribe, or reply to any email from us and we'll remove you.

If you sign in

We store your email address and the list of lessons you finished, so your progress follows you to other devices. Sign-in uses a one-time link sent by email (through Resend) and a cookie that keeps you signed in for up to 60 days. We don't use advertising or tracking cookies.

Analytics

We use PostHog to count visits and see which lessons people finish, so we know what to fix and what to build next. It records how you move through the pages (including anonymous session recordings) but never what you type into fields. Ad and tracking cookies are not used. Your browser's “Do Not Track” or an ad blocker may turn this off; the lessons work the same either way.

Feedback and votes

If you answer “Was this lesson clear?” or vote for the next module, we store your answer with a random id kept in your browser, not your name or email.

Where it lives

The site and its data run on Cloudflare. We never sell or share your data. To see or delete what we hold about you, reply to any email from us.