Fit Habit
A workout tracker for people who just want to keep showing up — and a lesson in building real device integrations with AI.
- Role
- AI development · Lovable → Claude Code Max
- Year
- 2026 · ~1 month validation, ~2 weeks build
- App Store
- App Store
Fit Habit is a strength-training companion built around calendar logging, automatic personal bests, and body-composition trends grounded in clinical ranges — iPhone, free, no streaks. It replaced the spreadsheet and the three apps I used to juggle to track lifting and bodyweight.
It was also where I learned to make AI build real, two-way device integrations rather than toy demos.
From Lovable to a production build
It started during the first weeks of my AI-development discovery. I used Lovable to spin up versions fast and validate the idea against my own daily use for about a month — disposable prototypes whose only job was to answer "is this worth building properly?"
Once the answer was yes, I rebuilt it for real with Claude Code Max in roughly two weeks: a production iOS app on a proper stack — Vercel, Supabase, Sentry, PostHog — and an App Store release. The hard part wasn't the UI; it was the integrations.
Apple Health & Withings
I learned to wire up two-way Apple Health sync — reading and writing workouts and bodyweight — and to pull body-composition data from the Withings API so trends line up against clinical reference ranges. Getting AI to handle real auth, permissions, and data round-trips taught me a lot about where it accelerates you and where you still have to drive.
