The brief
Athletes without a coach usually follow a bought plan or a spreadsheet. That plan was written before the season started and knows nothing about a bad night or a missed week. I wanted a coach that reads your own data and backs every piece of advice with numbers, even when the honest answer is to do less.
Built withExpoNext.jsSupabaseClaude API
What I built
- A coach that reads your data
The coach reads your sessions, sleep, HRV and resting heart rate, and adjusts your day to match. Every swap shows what both sessions cost in load. - Training science in code, not in a prompt
The maths for load, form and progression lives in tested code. Hard limits, like how fast your running volume may grow, are ones the coach cannot get around. - A season around your race
You pick one goal race and the hours you have. The app builds the season backwards from that date, for swimming, cycling, running and strength. - An admin built around privacy
An admin for athletes, subscriptions and what the coach costs. Health data is read-only there, and every view of it lands in an audit log.
The app
The app is the actual product. Athletes talk to their coach, follow their plan and see how their form develops. Built with Expo, for iOS and Android.
The coachEvery morning the coach reads your night and your heart rate. After three short nights it moves the hard session and explains why.
The planYour goal race at the top, today’s session and your week per sport. Everything you do counts towards the next piece of advice.
A sessionDuration, load and power for today, and where the session fits in your week. You can move it or ask the coach about it.
Your formFitness, fatigue and form over six weeks, and how you’re developing per sport. The coach points out what’s holding you back most.
The admin
Behind the app sits an admin in Next.js for whoever runs the platform. It shows what the business earns, what the coach costs and who may see which data.
01The overview
Monthly revenue, the number of athletes, what the AI coach costs and open support cases. The numbers come straight from the database, not from a separate analytics tool.
02Athletes
Everyone with an account, with their subscription status and whether onboarding is done. Whoever gets stuck along the way stands out straight away.
03Health data
HRV, resting heart rate and sleep are sensitive data. This page is read-only, and every time someone opens it, that goes into the audit log.
04The coaches
A head coach and six specialists, from physio to swimming. For each one you see which model it runs on, how much reasoning it gets and whether it’s in the free or the paid plan.
05Limits for the coach
Rules the coach cannot get around, like how fast your running volume may grow. Some refuse a plan, others only ask for an explanation. On top of that, the AI may only write a limited amount per athlete per day, so costs never run away.
06Revenue
Monthly revenue, subscribers and churn over ninety days, with what Stripe kept in fees and what was refunded.
07Retention
Per signup month: how many athletes are still active after one, two or six months. An empty cell means that month hasn’t happened yet, not that it’s zero.
Cadence Coach is still in testing. The athletes, sessions, health data and amounts in these screens are made up.
Need something similar?
A website for your business or club, or a tool that replaces a messy process. Email me your idea and I’ll let you know within a week whether it’s a fit.
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