Zef Downloads & RevenueZef · App Store
Not in any tracked top chart right now.
Updated 8 Nov 2026 · rankings refresh through the day
DeveloperDavid Kieffer
CategorySports
PriceFree
Released
Rating★ 4.7 (190)
Version2.8.7
Age rating4+
First seen by us
17 Oct 2026
17 Oct 2026Installs (est.)10k+ worldwide
📈Dropped out of every chart we track📈Entered the top 100🆕First spotted by AppInsider📦Version 2.8.7🆕Released on the App Store
Full timeline · 6 events
- 📈Zef dropped out of every chart we trackLast seen 5 Nov
- 📈Zef entered the top 100Top Grossing · Sports · BR
- 📈Zef charting in a new countryBrazil
- 🆕Zef first spotted by AppInsider#76 in Top Grossing · Sports · France
- 📦Zef version 2.8.7bug fix
- 🆕Zef released on the App Store
Collected from the stores by AppInsider since we first spotted the app. Dates are when we saw each change.
Rating
4.7 ★
190 ratings
Measured
Zef on the App Store
App details
App ID
1447673572
Publisher
David Kieffer
On the store since
Jun 2019
7 years on the store
Minimum OS
iOS 15.0+
iPhone 6s and later
Devices
iPhone · iPad · Watch
Universal purchase
Content rating
4+
Languages
1
EN
Size
45 MB
Also listed in
Navigation
Zef downloads
Worldwide, per day, and installs to date. The band is open; the exact number is free with an account.
How this is calculated
Apple publishes no download counts. App Store downloads come from chart positions and daily rating growth per country, calibrated on Google Play install counts; lifetime installs from ratings worldwide × installs per rating. Confidence is the chance the real number is within half to double ours.
Active users
All platforms, worldwide. Free with an account.
Stickiness (DAU / MAU)
how many monthly users open it on a given day
How this is calculated
Monthly users come from lifetime installs across every store, fitted on monthly active user figures companies publish; daily users = monthly × the typical daily/monthly ratio for the category. Confidence is the chance the real number is within half to double ours.
Where it ranks now
Every top chart it appears in across 30 countries.
| Country | Charts | Rank |
|---|---|---|
| Not charting right now. | ||
Ratings
App Store, worldwide.
Rating
4.7 ★
190 ratings
Measured
Ratings
190
Measured
Review momentum
ⓘ How we measure thisNew ratings a week
under 1
4-week average
Lifetime rating
4.7★
recent stars not readable yet: new ratings are a tiny share of the total
Review momentum
20/100
faster than 0% of Sports apps
Review momentum (0-100) blends how fast the app collects ratings compared with other apps in its category (60%), whether that pace is speeding up (25%) and what recent raters give it (15%; recent stars well below lifetime pull it down). Ratings counts are read daily. A jump usually means a launch, a feature, ads or a new review prompt.
About Zef
Zef — Ride. Track. Connect.
Zef is a multi-sport tracking app built for riders, with a strong focus on nautical sports.
Track your sessions, analyze your performance, discover spots, and see your friends live — all in one app.
Key Features
Track your rides
Record your sessions with your iPhone or Apple Watch.
Zef integrates with the Health app and supports GPX imports from most watches.
Advanced performance analytics
Get detailed session stats including speed, distance, duration, speed polar, and health data.
Sessions can be replayed to analyze each maneuver.
Jump analysis
Measure jump height using only your iPhone or Apple Watch.
Powered by algorithms inspired by drone technology.
Races & challenges
Create private or public races for training or competition.
Visual guidance and wind angles are displayed directly on your iPhone or Apple Watch.
Spots & live activity
Discover spots around you and see when riders are active.
Follow spots and get notified when sessions start.
Friends & live tracking
Follow riders by username and get notified when friends go live.
Watch their sessions live on the map and stay connected.
Supported Sports
Sailing, Windsurfing, Kitesurfing, Wingfoil, Kitefoil, Windfoil, SUP Foil, Surfing, Wakeboard,
Kayaking, Paddling, Snowkiting, Landkiting, Cross-country skiing, Skating,
Bike, Electric Bike, Parawingfoil, and more with custom tags.
Apple Ecosystem
• iPhone & Apple Watch support
• Health app integration
• Optimized for the Apple ecosystem
Important
Sessions must be recorded from the ground to be validated.
Legal
Terms of Service
https://zef.watch/terms-and-conditions.html
Privacy Policy
https://zef.watch/privacy-and-security-policy.html
Zef is a multi-sport tracking app built for riders, with a strong focus on nautical sports.
Track your sessions, analyze your performance, discover spots, and see your friends live — all in one app.
Key Features
Track your rides
Record your sessions with your iPhone or Apple Watch.
Zef integrates with the Health app and supports GPX imports from most watches.
Advanced performance analytics
Get detailed session stats including speed, distance, duration, speed polar, and health data.
Sessions can be replayed to analyze each maneuver.
Jump analysis
Measure jump height using only your iPhone or Apple Watch.
Powered by algorithms inspired by drone technology.
Races & challenges
Create private or public races for training or competition.
Visual guidance and wind angles are displayed directly on your iPhone or Apple Watch.
Spots & live activity
Discover spots around you and see when riders are active.
Follow spots and get notified when sessions start.
Friends & live tracking
Follow riders by username and get notified when friends go live.
Watch their sessions live on the map and stay connected.
Supported Sports
Sailing, Windsurfing, Kitesurfing, Wingfoil, Kitefoil, Windfoil, SUP Foil, Surfing, Wakeboard,
Kayaking, Paddling, Snowkiting, Landkiting, Cross-country skiing, Skating,
Bike, Electric Bike, Parawingfoil, and more with custom tags.
Apple Ecosystem
• iPhone & Apple Watch support
• Health app integration
• Optimized for the Apple ecosystem
Important
Sessions must be recorded from the ground to be validated.
Legal
Terms of Service
https://zef.watch/terms-and-conditions.html
Privacy Policy
https://zef.watch/privacy-and-security-policy.html
Latest updates
2.8.7
bug fix