Weight Ledger

A personal weight tracker that runs as a PWA on your phone. Reads weight from scale photos via the Anthropic API.

Contents

• index.html — the app (React, Recharts, Lucide, all via CDN, no build step)
• manifest.json — PWA manifest
• service-worker.js — offline cache + installability
• icon-192.png, icon-512.png — home-screen icons
• apple-touch-icon.png, favicon.png — iOS and browser icons

Deploy

Requirement: HTTPS. The camera API and service workers only work over HTTPS. All options below provide this automatically.

Option A — GitHub Pages

1. Create a public repo (e.g. weight-ledger)
2. Upload all files to the repo root
3. Settings → Pages → Source: main / root → Save
4. Visit https://<username>.github.io/weight-ledger/ after ~1 min

Option B — Netlify (drag-and-drop)

1. Log in to netlify.com
2. Drag the folder onto the deploy area
3. Get a URL like https://<random-name>.netlify.app/
4. Optionally rename in Site settings → Domain management

Option C — Vercel

Similar to Netlify. Import or drag the folder, get a URL.

Install on your phone

Android (Chrome)

1. Open the URL
2. A bar appears: "Install app" → tap it
3. If no bar: browser menu → "Install app" / "Add to Home screen"

iOS (Safari — not Chrome)

1. Open the URL in Safari
2. Share button → "Add to Home Screen"

First launch

1. Open Settings (gear icon, top right)
2. Set your height
3. Tap "Add key" under API Key, paste your Anthropic API key
4. Start logging — tap the + button

The API key is stored in your device's localStorage. It never leaves your phone except in requests to api.anthropic.com.

Updates

The service worker caches files for offline use. To force updates after you change code:

1. Bump CACHE_VERSION in service-worker.js
2. Redeploy

The next time the app is opened, the new version installs in the background. The launch after that shows the new version.

Data

• Everything lives in localStorage on your device.
• Export JSON from Settings for backup.
• Import JSON restores data (merges with existing; dedupes by timestamp+weight).
• "Clear all data" wipes entries but leaves the API key and height.

Troubleshooting

• Camera doesn't open: HTTPS missing, or site permissions blocked. Check browser site settings.
• "API error 401": API key is invalid or revoked. Update it in Settings.
• "API error 429": You've hit the rate limit or monthly spend cap. Check console.anthropic.com.
• App won't update after redeploy: Close the app fully, reopen; it may need two launches. Or clear site data in browser settings.