Privacy
To play on systemdesigner.io you sign in with a free Google or GitHub account. Reading the problems, lessons and guides needs no account. If you run your own copy of the code, no account is needed at all.
What you share to play here: the sign-in provider’s id for you, your email address, a display name, your avatar's web address, and the progress and scores you make. Details are below. Nothing is sold and there are no ad trackers.
Progress, drafts and settings live in your browser. The game's own usage counts and error reports are disabled on public sites.
Anonymous counts and feedback
The game itself sends us no automatic usage counts or error reports, including when an older saved setting enabled them.
Pages are served through Cloudflare, which counts page visits and load speed with its Web Analytics script. Cloudflare says the script uses no cookies or browser storage and doesn't fingerprint visitors. Our own server keeps no log of page requests.
Feedback is your choice. We keep your 1 to 5 rating, optional comment, the page or problem, game version and date. It is anonymous, even when you are signed in, unless you agree to be quoted. Please leave personal details out of comments you do not want attributed to you. Counts are kept for 13 months and feedback for 2 years, then cleanup removes them from the database and retained backups.
The form also asks optional questions about whether the game helped, what you used it for, your country and your role. We keep those answers with your feedback. You choose your country. We never infer it from your IP address or browser. If you agree to be quoted, we also keep your name, role and permission. We may quote your comment with that name and role on this site and in documents about System Designer and our work. Only then can you add an email for a follow-up about your quote. We keep quotes for 2 years and email for 12 months. To request removal, open a GitHub issue without posting your email or other private details. Backups expire within 7 days.
What we store when you sign in
- Your sign-in provider's id for you: the account number Google or GitHub gives this game. It is how we recognise you next time.
- A display name: your first name from Google or your GitHub name. You can change it anytime in the account menu. It appears on leaderboards and on "beat my design" links you share.
- Your avatar's web address, so your picture shows in the account menu.
- Your progress: solved problems, best scores, finished lessons and the days you played (for your streak).
- Your scores: your best score on each problem, with its stars.
- Your email address: the verified address Google gives us, or the primary verified address on your GitHub account. If your GitHub account has no verified address, we store none and sign-in still works. We keep it to have a way to contact you about your account. It is updated each time you sign in.
- Your survey choice: a yes or no, and the date you said yes. It starts as no. We email you short surveys and product updates only if you tick "Email me short surveys and product updates" when you sign in or in Settings.
- A sign-in cookie that keeps you signed in for 30 days. The server keeps only a scrambled (hashed) copy of it.
- A one-time sign-in code, only while you sign in with Google: a cookie that lasts at most 10 minutes and is deleted as soon as you are signed in. It makes sure the sign-in really came from your browser.
What we never store
- Your password. We never see it.
- A GitHub access token. GitHub sign-in asks only to read your email addresses (the user:email permission) and your public profile. The one-time token is thrown away right after we read them.
- Your email in a list we sell, rent or give to anyone. It is not shown on leaderboards, in shared links or in feedback. The only other email address we ever keep is the optional one you add to a quote.
- Advertising trackers, an identity attached to usage counts, or your sign-in identity attached to feedback. A quote keeps only the name and role you choose to give, plus an optional email.
Why we keep your email, and how to stop surveys
Two reasons. It is a way to reach you about your account. And, only if you tick the survey box, we use it to send short surveys and product updates. We do not send anything else. To stop, untick the box in Settings (under Email) at any time. It takes effect at once, and every message we send says the same. Deleting your account removes the address as well.
Who sees what
Anyone can see the leaderboards: display name, score, stars and rank. Your progress and your email address are visible only to you and to the person running this site. Nothing is sold or rented. If you agree to be quoted, your comment, name and role may be shared as described above. Your quote email is used only for a follow-up.
Delete it anytime
Open the account menu in the top bar and choose Delete my account. Your name, email address, avatar address, survey choice, synced progress and scores are removed from the server at once. Nightly backups roll off within 7 days. Progress saved on your own device stays there until you clear it in Settings. Deleting your account does not remove a quote, because quotes are not linked to your account. Request quote removal through the GitHub issues link below.
Questions
System Designer is free and open source. Ask anything by opening an issue at github.com/adityareddy-dev/system-designer.
Last updated November 12, 2026: we now store your email address.