Product
Only Tennis
Tag every point from your wrist while you play. The match records itself into stats, opponent history, and surface trends.
Only Tennis is a free iPhone and Apple Watch app for amateur tennis players. Players tag each point from their wrist during the match, and the app turns those points into the score, match statistics, head-to-head history against each opponent, and performance trends by surface. It is built and operated by Cazullo as a lab product: it is not a client project and it is not licensed, it is free on the App Store.
The problem it solves
An amateur player finishes a match knowing the result but not the reason. Memory rewrites the match on the drive home: the double faults fade, one good winner gets replayed all week, and the pattern that actually decided the set disappears. Serious stat tracking exists, but it assumes a coach, a camera, or somebody in the stands with a clipboard. Only Tennis puts it on the wrist of the person playing: tag the points as they happen, and the match records itself.
Who it is for
- Amateur and club players who want to know what actually decided the match, not what they remember about it
- Coaches who want a point-by-point record of a student's match without standing courtside with a notebook
- Weekend players who face the same opponents over and over and want an honest head-to-head history
What is included
Point tagging from the wrist
Record each point with a swipe on the Apple Watch, between points, while the match is happening. No phone in your pocket and no reconstructing the match afterwards.
Score and stats, automatically
The app keeps the score and builds the match statistics out of the points you tagged, so what you get at the end is a record rather than an estimate.
Head-to-head history
Every opponent carries a history: what happened last time, what keeps happening, and what actually changes when you play them differently.
Trends by surface
Performance broken down by surface, because almost nobody is the same player on clay and on hard court.
Match notes and gear
Conditions, notes about the opponent, and your racket setup stay attached to the match, so the numbers keep the context that explains them.
Community tournaments
Players compete in tournaments inside the app's community, against people who track their matches the same way.
How it works
- 01Start the match on the Apple Watch before the first serve
- 02Tag each point from your wrist with a swipe, between points
- 03The watch keeps the score and syncs the match to the phone
- 04The match turns into statistics, head-to-head history, and surface trends
- 05Notes about conditions, opponent, and gear stay attached to that match
- 06Over a season, the pattern surfaces: what wins points and what leaks them
Under the hood
Only Tennis is a native iOS and watchOS app built with Swift and SwiftUI, with a Firebase backend on Google Cloud. The watch app is not a companion screen: it holds the live match and syncs it to the phone, which is why tagging points works with the phone still in the bag. It is built and operated by Cazullo, a Miami software house.
Why a software house ships a tennis app
Only Tennis is a lab product. It is free, it is not a client project, and it is not licensed to anyone: Cazullo built it because the team plays tennis and the app it wanted did not exist. What transfers is the engineering: a wrist interaction that has to work in one tap between points, a watch-to-phone sync that cannot lose data, and a consumer app that ships and stays maintained. That is the same problem as a field app for a technician, or any workflow where the person's hands are busy and the data has to be captured at the moment it happens.
FAQ
Is Only Tennis free?
Yes, completely free on the App Store: no subscription, no paywall, and no premium tier.
Do I need to carry my phone on court?
No. The live match runs on the Apple Watch and syncs to the phone afterwards, so the phone can stay in the bag.
Is this built for professional players?
No. It is built for amateur and club players, coaches, and weekend players. Professionals already have teams, cameras, and analysts; this is for everyone else.
Does Cazullo license Only Tennis to other companies?
No. It is a lab product, built and operated in-house and free on the App Store. What Cazullo does offer is building this kind of software: native iOS and watchOS apps with real-time wrist interaction and a backend that keeps the data.
Can Cazullo build something like this for my sport or my operation?
Yes, and that is the point of a lab product. The engineering behind Only Tennis, a watch app that captures data in one tap, syncs reliably, and turns it into history and trends, applies to any operation where the person's hands are busy and the data has to be captured at the moment it happens.