What it is
FIT is a fast workout timer for a home gym. It runs in a browser or as a home-screen app on an iPad, picks a workout from a small library, and walks you through it round by round with audio cues. The thing that makes it different is that it knows you only have one of each weight.
How it started
My wife and I were getting ready to do a workout in the garage. She wanted something strength-focused, Tabata-style, with the kit we actually had. I went to find an interval timer app and got annoyed within thirty seconds at the same problem I'd hit before: every timer assumes you can just hand the same kettlebell to two people at once. We have one 15kg kettlebell, one 10kg, one barbell, one set of rings, a skipping rope, and a long gravel driveway. Two people can't both do swings on the heavy KB at the same time.
So I went into Claude Code, described what I wanted, told it the equipment list, and asked it to build me a workout timer that understood the constraint. With the GitHub and Vercel connections plumbed in, the build went straight from prompt to a live URL we could open on the iPad. About fifteen minutes from the first message to walking back out to the garage with our phones in our pockets and the timer running on the wall.
We did the workout blind. First run, no review. It worked really well.
What it actually does
The library has eleven workouts at the moment, from ten to forty-five minutes, filtered by time and focus area: whole body, upper, lower, core, or stretching.
Each workout knows who's doing what:
- Round-by-round assignments for one or two people
- Weight swaps mid-block so the heavy KB switches hands cleanly
- An injury alternative for every movement
- Audio cues that tell you what's coming, not just when
The constraints are the brief. If two people are in, the assignments respect the one-of-each-weight reality. If one person's in, the same workouts collapse to a solo flow.
How it's built
One static HTML file. No build step, no framework. Inline CSS, inline JavaScript. Teal Flaux palette with a few gradient touches. Designed for an iPad on the gym wall, so the text is big and the timer is unmissable from across the room.
Hosted on Vercel at fit.flaux.com.au. Source at github.com/TNCC01/flaux-fit.
The bigger lesson
The story I keep coming back to with this one is the fifteen minutes. The reason it landed that fast wasn't that AI is magic. It's that I'd already done the boring groundwork: a connected GitHub account, a Vercel project pattern that auto-deploys on push, a brand palette and logo system that snapped in without thinking, and a habit of describing constraints rather than handing over a vague brief.
The AI did the typing. The setup is what made it possible to type, run, and use in the same session.
Status
Live and in active use. Refining as we go: adding HIIT workouts, every-minute-on-the-minute formats, more variety in the existing categories. The shape works, the library grows.
