Zef is made and published by David Kieffer. AppBrain is an independent app data site and isn't affiliated with David Kieffer. The app name, icon, screenshots and description belong to David Kieffer and are shown as published on the App Store.
AppBrain's verdict
Established- Rating on App Store
- 4.61
- 41 ratings
- Last updated
- August 27, 2026
It doesn't have enough ratings yet to judge what users think.
Rankings
App Store top chartsApp Store Rankings for Zef
Competitors
Similar apps and more from David KiefferAlternatives to Zef
Also available on Google Play
Releases
Updates seen on the App Store- Version
- 2.8.7
- Launched
- June 2019
No changelog data
User feedback
Ratings and reviews on the App StoreComments on Zef for iOS
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Technology
Found in the app by AppBrain- Price
- Free
- App size
- 42.5 MB
- Content rating
- Everyone
Technologies used by Zef
About the app and developer
About Zef
Zef is a sports app developed by David Kieffer.
User Ratings
Zef is rated 4.61 out of 5 stars. The rating is based on 41 ratings.
App Information
Zef is freely available from the App Store. The app size is 42.51 MB. The latest version available is 2.8.7. The last update was on August 27, 2026.
Technical Requirements
The app has a content rating of Everyone. The app has been available on the App Store since June 2019.
Developer information for David Kieffer
Address:
Frequently asked questions about Zef
Is Zef free?
Yes. Zef is free on the App Store.
Is Zef still available?
Yes. Zef is on the App Store, and the last update we saw was on August 27, 2026.
How large is Zef?
Zef is 42.51 MB.
Is Zef suitable for children?
App Store rates the content of Zef as suitable for everyone.
How do people rate Zef?
Zef scores 4.61 out of 5 stars, from 41 ratings on the App Store.
Who made Zef?
Zef was developed by David Kieffer. It is listed in the sports category on the App Store.
What are the best alternatives to Zef?
People looking at Zef also look at these sports apps: Hoolan: Kite Wingfoil Windsurf, DUOTONE Wing Academy, DUOTONE Kiteboarding Academy, The Kite Mag, SportsTrackLive: Action Sports.
Store listing
By David Kieffer, from the App Store
Description by David Kieffer Written by the developer, not by AppBrain. Click to read.
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