About TONND

Why this exists

I have a Fitbit on my wrist, a Renpho scale in the bathroom, and Hevy on my phone for workouts. Three devices, three apps, three dashboards. None of them talk to each other. I can't look at my sleep data next to my HRV next to my training volume and see what's actually going on.

Then in July 2024, Google killed the Fitbit web dashboard. Millions of people lost the only way to look at their health data on a real screen. The phone app stayed, but the detailed analysis, the long-term trends, the stuff you actually need a monitor for? Gone.

So I built TONND. One dashboard for everything: sleep stages, HRV, VO₂ Max, SpO₂, weight, body fat, muscle mass, workout volume, recovery scores. Connect your Fitbit, Renpho, and Hevy, and it all shows up in one place. You can look at 7 days or 30 days. You can see which muscles you worked this week as a heatmap on a body diagram.

Who I am

I'm Wahed Hemati. I have a PhD in computational linguistics (natural language processing, specifically) and I've been building software for a while. I live in Frankfurt.

I started tracking my weight in Excel when I was 12. Bathroom scale, manual entry, formulas to calculate weekly averages. I was a chubby kid trying to figure out what worked. The devices got better over the years but nobody ever built the thing that brings it all together. I kept waiting for Fitbit or Apple or Google to do it. They didn't. So here we are.

I also built ceve.guru, an AI resume builder for the German job market.

How it's built

The whole thing is open source (AGPL-3.0). Backend is FastAPI with PostgreSQL. Frontend is React and TypeScript. You deploy it with Docker Compose. Auth goes through fastapi-users (JWT + Google OAuth). Fitbit tokens are Fernet-encrypted at rest. There's a scheduler that syncs everything daily.

For the workout muscle data, I pull the actual muscle groups from the Hevy exercise template API instead of trying to guess from exercise names. Each exercise gets its real primary and secondary muscles, weighted proportionally. The result shows up as an interactive body heatmap you can click on.

How I think about this project

Data is stored on EU servers in Frankfurt. I don't run ads, I don't sell data, I don't share it with anyone. If you want even more control, self-host the whole thing on your own hardware.

The code is on GitHub. All of it. The database is plain PostgreSQL, so you can export or back up your data whenever you want. There's no lock-in.

I don't do gamification. There are no streaks, no badges, no push notifications trying to get you to open the app. Just your data, your trends, and the context you need to make sense of them.

Where TONND is now

Phase one (done): all your devices in one dashboard. Fitbit vitals, Renpho body composition, Hevy workouts, recovery scores, muscle heatmaps. 15+ metrics unified.

Phase two (done): TONND connects to Claude via the Model Context Protocol. You can ask your health data questions in plain language. No code, no exports. Just connect your TONND account in Claude.ai and start asking.

Phase three (in progress): the AI notices things you didn't ask about. HRV trending down while training volume is up. Sleep efficiency dropping every Sunday. Recomposition happening even though the scale isn't moving.

TONND is a data tracking tool, not a medical device. Recovery scores and training insights are based on your personal data and general research, not clinical guidance. Consult a healthcare provider for medical decisions.

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