kcal

A personal food and workout tracker. Take a photo of a meal, get an itemised calorie and macro estimate from Claude, correct it if needed, and save it against a daily calorie limit. Log workouts and weight alongside.

Setup

npm install
cp .env.example .env.local   # add your Anthropic API key
npm run dev

Open http://localhost:3000. On a phone, add it to the home screen for an app-like experience.

Deploy

The photo analysis runs in a server route (app/api/analyze/route.ts) so the API key never reaches the browser. That means the app needs a Node host, not static hosting. Vercel is the simplest option:

1. Import the repo on Vercel.
2. Add ANTHROPIC_API_KEY and APP_PASSWORD as environment variables.
3. Deploy, open the site on your phone, and enter the same password under Settings → App password.

The analysis route refuses requests without the password and caps each IP address at 40 analyses an hour (ANALYZE_RATE_LIMIT to change). Without that, anyone who found the URL could spend your Anthropic credits.

Model and cost

Photo analysis uses Claude Sonnet 5 by default. A typical meal photo plus the itemised answer is roughly 3,000 to 4,000 tokens, which works out to around one to two US cents per meal. Set ANALYSIS_MODEL to change it:

Model	Env value	Rough cost per meal
Haiku 4.5	claude-haiku-4-5	under 1 cent
Sonnet 5 (default)	claude-sonnet-5	1 to 2 cents
Opus 5	claude-opus-5	3 to 5 cents

Data

Meals, workouts, weights, and settings live in the browser's localStorage on the device you use. Use Settings → Export backup to save a JSON copy, and Import backup to restore it on another device. Imports are validated against the app's schema before anything is overwritten, and a save that fails because the device is out of storage is reported instead of silently lost.

Offline

A service worker caches pages and build assets as you use them, so the app opens offline on any device that has visited it while online. Photo analysis needs a connection.

Scripts

• npm run dev – local dev server
• npm run build – production build
• npm run typecheck – TypeScript check
• npm run lint – ESLint