HeadwindLabRun · Ride · Swim · iPhone and Apple Watch
Apps for endurance athletes.
I train for long races and build iOS apps. Each one here fixes a problem I kept running into in my own training. No accounts, no ads, no subscriptions.
The apps
App StoreFuel Perfect
Put in your race, how much you sweat and what your gut can handle.
Race fueling planner · iPhone
App StoreSwim Structured
Coaches write swim workouts as text.
Swim workouts on your wrist · iPhone and Apple Watch
App StoreTrueWatt
Your smart trainer and your power meter never agree.
ERG mode from your power meter · iPhone
Coming soonTriCoach
TriCoach reads your training from Apple Health, Strava or intervals.icu and builds your swim, bike and run plan backwards from race day.
Triathlon training plans · iPhone
App StoreLiveHeat
LiveHeat connects your Apple Watch straight to your CORE sensor and shows your body temperature every second.
Core temperature on your wrist · Apple Watch
About
Built in the hours before work.
I'm Nils. I run, ride and swim in California and build toward long races. My best day so far was 9:32 at IRONMAN California in 2025. Like most people with a job, I fit training in around everything else.
These apps came out of that. I was under fueling, so I built a fueling planner that shows its sources. My trainer and power meter never agreed, so I made the power meter run the trainer. My coach sends swim sets as text, and I wanted them on my wrist without retyping.
Everything runs on your phone or watch. Nothing is sold. If something breaks or you want a feature, email me. I read every message.
SymboCalc
WindWaterSail