Training intelligence for iPhone and Apple Watch
Train smarter. Share nothing.
Aethr turns the workouts already in Apple Health into pro-level analytics, computed entirely on your iPhone. No account, no cloud, no subscription.
One model for every sport
Fitness, fatigue, form.
Every run, ride, hike, walk and ski day becomes one training-load score. Aethr tracks how fit you are, how tired you are, and whether today is the day to go hard.
Built for hills
Every climb, measured.
Climbs are detected, categorised from Cat 4 to HC and painted by gradient. Grade-adjusted pace keeps uphill effort honest, and any climb becomes a shareable Ascent Story.
Privacy by architecture
It all stays on your phone.
No Aethr servers exist to send your data to. Your heart, your routes and your sleep belong to you, not to a leaderboard or an ad network.
Privacy by architecture
Your training data never leaves your iPhone.
Most training platforms are cloud services first. Aethr was built the other way round: the analytics engine lives on the device in your pocket, so there is nothing to upload.
- 01
No account. Ever.
No sign-up, no email, no password. Open the app, connect Apple Health, done.
- 02
No Aethr servers
Every number is computed on your iPhone. There is no cloud copy of your training for anyone to sell, leak or lose.
- 03
Apple Health is the source
Aethr reads what is already in Health and keeps only derived analytics. Delete the app and they are gone.
- 04
No trackers, no ads
No analytics SDKs, no ad networks, no data brokers. We sell software, not you.
Weather comes from Apple WeatherKit and maps from Apple Maps, so those requests go to Apple, never to us. Details in our Privacy Policy.
- Training load
- Fitness CTL
- Fatigue ATL
- Form TSB
- ACWR
- Normalized power
- Intensity factor
- Power curve
- Critical power
- W′
- Grade adjusted pace
- VDOT paces
- Critical speed
- Aerobic decoupling
- Efficiency factor
- HR recovery 60 s
- HR recovery 2 min
- Climb categories
- VAM
- Run / walk detection
- Interval reps
- Heat-adjusted pace
- FIT import
- Sleep score
- Gear mileage
- HRV trend
- VO₂max
The app
Pro-level analytics, from the workouts you already record.
Know how ready you are
Form, fitness and fatigue, sleep score with stages, load ratio and HRV. One glance tells you whether today is for intervals or for recovery.
- TSB form gauge
- Sleep score
- ACWR
- HRV
01 / 09
ImportGarmin, Polar, Suunto, COROS
FIT, GPX and TCX files go straight into Apple Health, routes and power included.
GearShoes, bikes and skis
Mileage per item and a reminder when it is time to replace.
MonthlyRoute heat map and recap film
Every route of the month on one map, and a story that draws them in.
ShareCards, stickers and GPX
Route art, stats stickers and climb videos, rendered on the phone.
Five sports, one load model
Run, ride, hike, walk and ski. All of it counts.
One training-load score makes a hilly hike, a threshold ride and an easy jog comparable, so your fitness curve tells the truth about every session.
- Run
- Ride
- Hike
- Walk
- Ski
Apple Watch
Record on the wrist. Understand on the phone.
The Aethr watch app records runs, rides, hikes, walks, intervals and sprint sessions, pairs chest straps and power meters, and hands everything to Apple Health. Already use the Workout app or another watch? Aethr reads those too.
Run
Pace, HR, distance and running power on the wrist.
Cycle
Speed, HR and Bluetooth power and cadence sensors.
Hike
Live ascent, altitude and grade.
Sprint
Every sprint detected and lapped automatically.
The honest comparison
Serious analytics without renting them back every month.
The others are good products. They are also cloud services with accounts and subscriptions. Aethr gives you the training science and keeps the data where it started.
| Feature | Aethr | Strava | TrainingPeaks |
|---|---|---|---|
| What you pay | Free core, €11.99 once for Pro | $79.99 / year subscription | about $134.99 / year for Premium |
| Subscription | Never | Yes | Yes |
| Account required | No | Yes | Yes |
| Where your workouts live | Only on your iPhone | Strava's cloud | TrainingPeaks' cloud |
| Fitness, fatigue and form chart | Included in Pro | Subscribers only | Premium only |
| Native iPhone app | iPhone and Apple Watch | Yes | Yes |
| Works without uploading anything | Yes | No | No |
Competitor details from their public pricing pages and docs, October 2026. Prices exclude tax and can change. Strava and TrainingPeaks are trademarks of their owners and are not affiliated with Aethr.
Pricing
Pay once. Own it.
Aethr
Free download
- Every sport recorded on Apple Watch, with guided intervals and sprints
- Full detail for every workout: map, splits, charts, climbs and weather
- Personal bests, share cards, climb videos and GPX export
- One gear item per sport and Apple Health sync both ways
- No ads, no account, no time limit
Lifetime
Aethr Pro
€11.99 once, no subscription
- Trends: fitness, fatigue and form, pace and power curves, 80/20 check
- Monthly summary with route heat map and recap film
- Advanced records: VDOT paces, critical speed, threshold suggestions
- Readiness guidance on Today, unlimited gear, FIT, GPX and TCX import
- Every future improvement to these screens
Buy once, own forever. Family Sharing included.
Aethr Pro is a one-time in-app purchase through the App Store. Prices are shown in euro; your local App Store price and taxes apply. Purchases are handled by Apple and tied to your Apple Account.
Shape what we build next
What should Aethr do next?
Aethr is made by a two-person team in Bratislava. Feature requests go straight to the people writing the code, and plenty of what is in the app today started as one.
Prefer email? info_aethr@kaslbi.com