Serve Review

Film a few serves, get the numbers: knee bend, contact height, torso rotation, and how consistent you were across the set.

Serve Review looks at your tennis serve and tells you what it actually did.

Record a few serves on your phone, or pick a clip you already have. Serve Review finds each serve, measures your body through it, and shows you the numbers — plus how much you varied from one serve to the next.

WHAT IT MEASURES

• Knee bend at the deepest point — the one number with a real reference: pros reach roughly 100–120° • Contact height, relative to your own height • Torso rotation between the backswing and contact • Toss drift — how straight your tossing arm travelled • Weight shift, swing time, arm extension • Consistency — how much each of those varied across your serves

HONEST ABOUT ITS LIMITS

A single phone camera sees a flat projection of a three-dimensional motion. We measured that error against public motion-capture data instead of guessing at it, and the app says out loud which numbers are accurate enough to judge against a standard and which are only worth comparing against your own other serves. Arm extension, for example, is explicitly not given a verdict — two cameras measuring the same arm disagreed by 22.6°, and that is not accurate enough to tell you whether your arm was straight.

EVERYTHING STAYS ON YOUR PHONE

Videos are analyzed on the device. Nothing is uploaded, no account is needed, and the app works with no network connection at all.

PRICING

Three analyses free. After that, one payment unlocks it forever — no subscription, no monthly fee. Same Apple ID on a new phone: tap Restore Purchase.

WHAT IT DOES NOT DO

It does not track the ball, call lines, or keep score. It reads your body, not the game. Forehands and backhands are counted but not scored — the measurements that would matter there are swing speeds, and a single phone camera cannot measure those accurately enough to be worth showing.