Privacy
The short version: we barely track you.
You can use every part of TopSpin — analysis, drills, the Ball Lab, stats — with no account at all, and if you do, we still collect nothing personal beyond what you give us. No ad trackers or analytics cookies. Signed-in accounts use essential session cookies. Accounts are optional, and exist mainly so a player can chooseto connect with a coach. Here's exactly what's stored, and when.
What we collect
- • An anonymous id kept in your browser's local storage. It isn't tied to your name or email; it just tells a returning browser from a new one.
- • The page paths you view (e.g.
/learn). Query strings are stripped before anything is stored. - • A tally of analyses, simulations, and workouts run. Just counts, with nothing tied to you.
- • The origin of the site that linked you here (e.g.
https://google.com), never the full URL.
What we never collect
- • No personal data at all unless you choose to make an account.
- • No advertising cookies and no third-party analytics, ads, or social pixels. Essential authentication cookies are used only while you're signed in.
- • No IP addresses stored. Your IP is used for a split second to rate-limit abuse, then discarded.
- • No mouse movement, scroll tracking, keystrokes, or device fingerprinting.
If you make an account (optional)
Only if you sign up, we store your email, your birth year (a single year, for the age check below — never a full date of birth), and the analyses you save(stroke, form score, flaws, serve estimate) so you can track progress. Auth is handled by Supabase. We don't see or store your password, and we never sell or share any of it. You can delete saved analyses or permanently delete the account from the account page.
Coaches, squads & connecting with one
A coach connection is opt-in. If you enter a coach's squad code, only a summary of your practice syncs to them — form scores, drills completed, and dates. Your video and full stroke breakdown stays private; sending a specific analysis breakdown to a coach is always a separate, deliberate choice. The clip itself stays on your device. Leaving the squad or deleting your account stops the sync and removes the summary data we held for that connection.
Younger players & parental consent
If your birth year says you may be under 16, you can still use the whole app on your device, but connecting with a coach needs a parent or guardian's approval first. For that we store the guardian email you provideand send them a one-time, expiring approval link. Nothing syncs to a coach until they approve, and they (or you) can undo it at any time. This is our good-faith approach to COPPA (US, under 13) and GDPR (under 16); it isn't legal advice.
Your video clips
Clip analysis runs entirely in your browser. Your video is never uploaded, never stored, and never leaves your device — with or without an account. Only the resulting numbers are saved, and only if you're signed in. When you close the tab, the clip is gone.
Shared summaries
If you create a shareable coach summary, it lives at a public link that anyone with the URL can open. It contains the stroke read and suggested drills, not your identity. Only make one if you're happy to hand out the link.
Coach notes and parent reports
A linked coach can add a short note only to an analysis you deliberately shared with that coach. Coaches can also create a report containing recent summary scores and practice counts. Reports use long, unguessable links and expire after 30 days. Anyone holding a report link can open it, so handle it like any other private link.
Where the data lives
Traffic counts sit in our own database; account data sits in Supabase. No analytics SaaS is in the loop. Anonymous traffic records are capped and old ones are pruned automatically.
Your control
Browsing anonymously, the only identifier lives in your browser, so you can reset it by clearing local storage. With an account, you can wipe your saved analyses from the account page, and ask permanently delete the account and its synced data from the account page.
Changes
If this policy changes, the new version lives here. Questions? See the about page.
TopSpin is a personal project. This is a good-faith, plain-English summary of how it handles data, not legal advice.