ProtocolOS
An offline-first fitness PWA — training plans, progressive-overload coaching, CrossFit WODs, and nutrition tracking — built entirely in vanilla JavaScript with zero backend.
Live app: flowopsai.co.il/fitness_app
ProtocolOS is a complete personal training system that runs 100% in the browser. All data lives in localStorage, the service worker keeps it working with no connection, and it installs to the home screen like a native app. The UI is in Hebrew (full RTL support).
Features
Training
- Push / Pull / Legs / Arms split with weekly scheduling — supports 1–7 training days per week, including A/B and A/B/C split variants
- Home-workout mode with three equipment tiers: bodyweight only, resistance bands, or dumbbells — the app resolves the active plan automatically from the user's equipment
- Exercise database of 100+ exercises, each with Hebrew and English names, set/rep schemes, rest times, difficulty level, target muscles, technique description, form tips, and exercise alternatives
- Integrated rest timer with Web Audio API beeps and device vibration
- Plate calculator and 1RM calculator (estimated one-rep max, updated when a PR is saved)
Progressive-Overload Coach
A rule-based coaching engine analyzes each exercise's logged history and tells the user what to do next:
- Detects stagnation (4+ identical sessions) and suggests changing the exercise or intensity
- Detects when the rep-range ceiling is hit repeatedly and prompts a +2.5 kg increase
- Detects when weight is too heavy (reps below range) and suggests a deload
- Per-exercise SVG sparklines visualize the last 6 sessions at a glance
CrossFit
- 20 curated WODs — benchmark workouts (Fran, Annie) and Hero WODs (Murph) plus home-friendly ones — in AMRAP, EMOM, and For Time formats with time caps
- Deterministic WOD-of-the-day rotation and score logging per workout
Nutrition
- BMR / TDEE calculation (Mifflin-St Jeor) with goal-based calorie targets — lean bulk, bulk, cut, maintain — and automatic protein/fat/carb macro split
- Daily food diary with product search powered by the Open Food Facts API
- Water intake tracker
- AI nutrition advisor: works fully offline with a built-in rule-based Q&A engine, and optionally upgrades to the Claude API (user supplies their own key, stored locally only)
Progress & Gamification
- Body-weight log with progress graph, body measurements, PR tracking, RPE and recovery logging, habit tracking
- XP system, streak-based achievement badges, and rotating weekly "boss challenges" (e.g. 100 push-ups this week, 5,000 kg total volume)
- Full JSON export/import for backup and device migration
App Experience
- Installable PWA with app shortcuts that deep-link straight into PUSH/PULL/LEGS/ARMS day
- Three themes: dark, light, and AMOLED
- Portrait-oriented, standalone display, RTL Hebrew UI
Tech Stack
| Layer | Choice |
|---|
| Language | Vanilla JavaScript (ES modules) — no framework |
| Offline | Service Worker + Cache Storage |
| Persistence | localStorage only — no backend, no accounts, no tracking |
| External APIs | Open Food Facts (food search), Claude API (optional, user-keyed) |
| Build | Vite + Terser minification |
| Testing | Vitest — pure logic extracted to src/pure.js for unit testing |
| CI/CD | GitHub Actions: test, then build and deploy to GitHub Pages on every push to main |
| Hosting | GitHub Pages behind a custom domain |
Architecture Notes
- Offline strategy (
sw.js): network-first for the app shell (HTML/JS/CSS) so users always get fresh code when online, with cache fallback when offline; cache-first for static assets (icons, fonts). Old caches are purged on activation and open clients are notified via postMessage when a new version is live.
- No backend by design. Every feature — workout logs, nutrition history, achievements — is computed client-side and persisted in namespaced
localStorage keys. The result: zero hosting cost beyond static files, instant loads, and complete data privacy.
- Data migration and backup are built in: state can be exported as a dated JSON file and re-imported on another device.
- Testable core: nutrition math, rep-range parsing, and sparkline generation live as pure functions in
src/pure.js, covered by Vitest and gated in CI before deploy.
Try It
- Open flowopsai.co.il/fitness_app on your phone or desktop.
- On mobile, choose "Add to Home Screen" to install it as a PWA.
- Turn on airplane mode — it keeps working.
Development
npm ci
npm run dev # Vite dev server on port 3000
npm test # Vitest unit tests
npm run build # production build to dist/
License
ISC
