Privacy Policy

Last updated: June 2026

Fitness OS is built on a principle of absolute data privacy. We collect only what is necessary to operate the service and never sell your personal data to third parties.

1. Data We Collect

Category	Data	Purpose
Account	Email address, hashed password	Authentication via Supabase
Profile	Age, weight, fitness goal, language preference	Personalizing workout recommendations and recovery calculations
Workout Logs	Exercise name, sets, reps, weight, date/time	Progress tracking, SRA recovery modeling, AI analysis
App Settings	Theme, timer preferences, Arsenal exercises	Persisting user preferences
Device	Browser type, OS (anonymous)	PWA functionality and crash reporting

We do not collect: GPS location, contacts, camera/microphone access (except Gym Lens with explicit user consent), or any biometric identifiers.

2. How We Use Your Data

To provide and improve the Fitness OS service
To calculate muscle recovery status using our SRA Bio-Engine algorithm
To generate AI-powered workout recommendations
To display your personal fitness progress and statistics
To send in-app notifications (rest timers, streak reminders)

3. Data Storage

Your workout data is stored in two places:

Local Storage — on your device, for offline access and instant performance
Supabase (cloud) — encrypted in transit (TLS) and at rest, hosted in the EU, for cross-device sync and backup

Supabase is our database provider. Their privacy policy is available at supabase.com/privacy. We enforce Row Level Security (RLS) so your data is accessible only to your account.

4. AI & Third-Party Services

When you use AI features (Gym Lens, AI Workout Generator, Weekly Summary), anonymized workout data is sent to our Cloudflare Worker proxy, which forwards requests to the Anthropic Claude API. We do not send your email, name, or any personally identifiable information to Anthropic.

YouTube video thumbnails are loaded directly from YouTube's CDN. This is subject to Google's Privacy Policy.

5. Data Retention

Your data is retained for as long as your account is active. You may delete your account at any time from the Setup → Profile tab, which permanently removes all your data from our servers within 30 days.

6. Your Rights (GDPR)

If you are located in the European Economic Area, you have the right to:

Access — request a copy of your personal data
Rectification — correct inaccurate data
Erasure — request deletion of your data ("right to be forgotten")
Portability — receive your data in a machine-readable format
Objection — object to processing of your data

To exercise these rights, contact us at privacy@fitnessos.app.

7. Cookies

Fitness OS uses only functional cookies and localStorage for session management and user preferences. We do not use tracking cookies or advertising cookies.

8. Children's Privacy

The Service is not directed to children under the age of 16. We do not knowingly collect personal information from children. If you believe a child has provided us with personal data, contact us immediately.

9. Changes to This Policy

We may update this Privacy Policy from time to time. We will notify you of significant changes through the application. Continued use of the Service after changes constitutes acceptance.

10. Contact

For privacy-related inquiries: privacy@fitnessos.app

Terms · Privacy