Privacy

Swing analysis — the recording you analyse

When you analyse a swing and you are online, the clip is uploaded to our analysis server (Modal, in the United States), which finds your body positions in each frame and sends the measurements back. The clip is processed in memory and is not written to disk or retained after the request completes — the video and every measurement end up stored on your device, not with us. If you are offline or the upload fails, the same analysis runs on your phone instead; it is slower there, and on some phones the phone's own video decoder cannot read imported slow-motion files at all, which is why the server does this job when it can.

3D reconstruction — only when you tap “Run 3D analysis”

Your browser crops each frame to the area around you, downscales it, and sends those images to a GPU service (Modal, in the United States) which returns a 3D skeleton. These are photographs of you. They are processed in memory to produce the skeleton and are not written to disk or retained by us or by Modal after the request completes. The video itself is never uploaded — only the cropped frames.

Clubhead tracking — only when you tap “Track the clubhead”

This one sends the CLIP ITSELF — the recorded video, as recorded, up to 24 MB — to the same GPU service, along with your hand and ankle positions so it knows where to look. It is the only feature that uploads video rather than cropped stills, because following a clubhead needs the frames either side of each one and the phone cannot do that work. The clip is decoded in memory to produce the track and is not written to disk or retained after the request completes. If you never tap it, your video never leaves the device.

AI coaching — when a report is generated

Numbers only: your measurements, which of them fell outside the reference corridors, the club, the detected swing archetype, and anything you entered in your player profile (handicap, typical miss, goal). No images and no video. This is sent to Anthropic's Claude via an API gateway to write the coaching text. If it fails, the app falls back to a rules-based report written from the same numbers.

Anonymous benchmarks — only if you opt in

If you choose to compare yourself against other golfers, the numeric measurements from that swing are added to a pool with your self-reported handicap band and club type. Nothing identifying is attached, and it cannot be traced back to you or your account.

Account and billing

If you sign in, we store your email address (via Supabase) to identify your account. If you subscribe, Stripe processes the payment — your card details go directly to Stripe and never reach us. We keep only the Stripe customer reference so we know what you have access to.

Analytics

Page views and real-device performance, collected by Vercel. Cookieless and not tied to your account or your swings. We use it to see which features get used and whether the app is fast enough on real phones.