Film a game. It finds your swings.
Phone on the fence, side-on, the way you would film anything. It walks the footage, finds every swing you hit, measures the ones it can track cleanly, and grades the ones it can name — then tells you how many it skipped, and why.
iPhone only, iOS 16.4 and up.
6
swings graded
- 11 found
- 8 measured
- 6 graded
- Third-Shot Drop ×3
- Drive ×1
- Dink ×2
2 it wouldn’t name. A swing it can’t name doesn’t get graded on a guess — a drive and a drop want opposite things.
The video never leaves the phone.
Pose tracking runs on your iPhone. What reaches a server is a table of numbers and up to 10 still frames with the skeleton drawn on them.
Failure is always free.
When it can’t produce an honest report it stops, says why, and doesn’t take a credit. That one is in the Terms, not just on this page.
Every number here came out of the code.
Not typed in. The build reads the shipped analysis pipeline and refuses to publish a page saying something the code can’t back.
01 How it works
Three steps, and the middle one happens on your phone.
1
Film a game.
Phone on the fence, side-on, whole body in frame. Closer is better — that one choice decides how much of your game it can read.
2
It finds every swing.
It walks the footage, picks out each swing you hit, and measures the ones it can track cleanly: shoulder turn, elbow angle at contact, how long the takeback took.
3
You get one fix and one drill.
Not a list of nine things across a whole game. The one that moves the most, and something to do about it on Tuesday.
02 The tracking
This is what happens to every swing it finds.
61 frames of real tracking off one of them, played at the speed it was filmed. The bones vanish wherever the tracker’s confidence drops under the line the app draws at. Nothing is drawn in — if it couldn’t see your wrist, you will see that it couldn’t see your wrist.
- Contact, 2,133 ms in — the bottom of the arc, which is where the app puts it.
- The wrist, from the start of the downswing to the end of the follow-through.
- Bones vanish under 0.3 confidence, the same threshold the app draws at: 18 of 1,037 tracked points across these 61 frames. Nothing is drawn in.
- 17
- body points tracked in every frame
- 61
- frames of real output in the panel above
- 27
- measurements taken off the swings it grades
- 18/1,037
- points it refused to draw, because it could not see them
03 Coverage
How much of a game it reads depends on how you filmed it.
Two real scans are in the repository and this page publishes both, because either one on its own would be a sales pitch. The difference between them is not the code. It is the camera.
A 76-second clip, filmed close in
- 11 swings found
the clip in the photograph at the top of this page
- 8 tracked cleanly enough to measure
3 never got through the tracking filters
- 6 graded
2 it would not name, and an unnamed swing is not graded on a guess
Ten minutes of doubles, filmed from further back
- 43 swings found
one full game, scanned end to end
- 20 tracked cleanly enough to measure
23 never got through the tracking filters
- 3 graded
9 dropped because the player is a small figure in frame and the pose model cannot find a wrist at that size; 8 it would not name, and an unnamed swing is not graded on a guess
A scan costs 2 credits. Under three graded swings there is no report at all — that is a failure, so it is free. Same code, different footage. In the long one the player is a small figure in frame and the pose model genuinely cannot find a wrist at that size — so the honest thing the app can do is measure what it can see and tell you about the rest. Coverage is the number I’m working on, and when it moves it moves here, because the fixture it is computed from changed rather than because I retyped it.
04 Shots
Four shots inside a scan, and two you can film one at a time.
A scan names serves, drives, dinks and third-shot drops. Of those, only the serve’s scoring scale has been fitted against labelled footage — the rest measure correctly, but their numbers are still directional, and the app says so on the report rather than in a footnote here.
You can also film a single serve or a single drive and have just that graded, which is the fastest way to see what the measurements look like.
27 measurements across 4 shots, and what each one is scored between →
05 The reading
Every part of the swing gets a number. One of them gets flagged.
- Body rotation 99/100all arm full turn
How much your shoulders turned through the swing.
- Weight transfer 60/100flat-footed full transfer
How much you moved forward into the shot.
- Head stability 44/100 · flaggedhead moving head still
How still your head stayed through the swing.
06 Price
Your first analysis is free. The rest costs less than one lesson.
Pro is $9.99 a month or $59.99 a year, and covers 20 analyses a day.
One in-person pickleball lesson runs $50–$100.
Everything is bought inside the app, so the App Store purchase sheet is the price that counts. A failed analysis never takes a credit.
07 Scope
What it isn’t.
- Not ball tracking. It never looks at the ball. It looks at you.
- Not scorekeeping, not shot placement, not a line judge.
- Not a DUPR rating. The band it shows is a form estimate printed on a scale you already recognise. Form-based estimate, not an official DUPR rating.
- Not a replacement for a coach who can watch you play a whole match. It’s for the weeks in between.
08 Questions
The things people ask first.
What does it actually measure?
Every swing it finds in your footage, one at a time. Seventeen tracked body points, then geometry off them: how far your shoulders turned, your elbow angle at contact, how much your knees loaded, how long the takeback took, how far the paddle carried after the strike. That is 27 measurements across 4 shots, each scored between two anchors you can go and read for yourself.
Which shots can it grade?
A scan names serves, drives, dinks and third-shot drops. You can also film a single serve or a single drive on its own. Of the four, only the serve’s scale has been fitted against labelled footage; the others measure correctly but their numbers are directional, and the report says so on itself rather than in a footnote here.
What does it cost?
Your first analysis is free. Pro is $9.99 a month or $59.99 a year and covers 20 analyses a day. It is bought inside the app, so the purchase sheet is the price that counts.
Where does my video go?
Nowhere. Pose tracking runs on your iPhone. What reaches a server is a table of numbers and up to 10 still frames with a skeleton drawn on them. The clip itself stays in the app, on your phone.
What do I need to run it?
An iPhone on iOS 16.4 or later, and that is it. There is no web version, and no version for any other kind of phone.
How do I film it?
Phone on the fence, side-on, whole body in frame, decent light. You want to fill roughly a fifth of the picture height, and that one thing decides more than anything else in the app: on a clip filmed close in it graded 6 of the 11 swings it found, and on a game filmed from further back it graded 3 of 43, almost all of the loss being that it could not find a wrist on a figure that small. It will tell you when that happens rather than guess.
What happens when it gets it wrong?
It costs you nothing. A failed scan never uses your free one and never takes a credit, and a scan that finds fewer than three clear swings is a failure by that rule. When the pipeline can’t produce an honest report it stops and tells you why instead of inventing something plausible — and when it can only measure part of a swing, it says which part it could not see.
Who is behind this?
One person. I built it, I answer the email, usually within a day or two. If something is broken or a number looks wrong, write to me and I will tell you what the code actually did.
Point it at your next game.
Your first one is free, you film it the way you already film anything, and if it can’t produce an honest report it costs you nothing.
iPhone only, iOS 16.4 and up.