Tetsu ("we", "us") is a fitness tracking app for iOS and Android. This policy explains what information the app handles, why, and the choices you have. The short version: your fitness data exists so the app can work for you — we don't sell it, we don't run ads, and you can export or permanently delete everything yourself, in the app, at any time.
| Category | Details | Why |
|---|---|---|
| Account | Email address and password, or your Google / Apple sign-in identity; name; date of birth; gender; height. | Creating and securing your account; age eligibility (13+); personalizing calculations such as calorie estimates. |
| Health & fitness data you log | Workouts, exercises, sets and personal records; body weight and body measurements; goals; meals and nutrition logs; daily activity (steps, water, sleep, wake times); dietary preferences and allergies you choose to enter. | The core function of the app: tracking your training, nutrition, and progress. |
| Progress photos | Photos you take are stored on your device only — they are never uploaded to our servers. We store only non-image metadata (date, angle, and the stats you attach). Your optional profile picture is uploaded to our storage. | Visual progress tracking; showing your avatar in the app. |
| Motion data | Step counts from your device's motion sensor, if you grant permission. | Counting daily steps toward your routine's step goal. |
| AI inputs | Free-text you type into AI features (e.g. routine requests, meal descriptions) and relevant profile context (goals, equipment, dietary preferences). | Generating your workout/nutrition plans and parsing meal descriptions. |
| Purchases | Subscription status and purchase history (processed by Apple/Google and RevenueCat). We never see your payment card details. | Unlocking and managing Tetsu Pro. |
| Diagnostics | Crash reports and error diagnostics (via Sentry), which may be linked to your account identifier. | Finding and fixing bugs. |
AI requests are proxied through our own server and forwarded to OpenAI to generate the response. We instruct OpenAI not to store the conversation for its own use, and API inputs are not used to train OpenAI's models under its API terms. Don't include information in free-text prompts that you wouldn't want processed this way. AI output is general fitness guidance, not medical advice.
Your account and fitness data are stored with Supabase on cloud infrastructure located in the United States. Data is encrypted in transit, and access is restricted per-account by row-level security.
Only the service providers needed to run the app: Supabase (database & authentication), OpenAI (AI responses), RevenueCat and Apple/Google (subscriptions), and Sentry (crash reporting). Each receives only what its function requires. We do not sell your personal information, and we do not share it with advertisers or data brokers.
We keep your data for as long as your account exists. Deleting your account removes it. Backend logs (such as crash reports) age out on short retention windows.
Tetsu is not directed at children under 13, and account creation enforces a minimum age of 13. If you believe a child under 13 has an account, contact us and we will delete it.
Depending on where you live (e.g. GDPR in the EU/UK, CCPA/CPRA in California), you may have rights to access, correct, export, or delete your personal information, and to lodge a complaint with your local authority. The in-app export and delete tools above satisfy most requests instantly; for anything else, email us and we'll respond within 30 days.
If we make material changes to this policy we'll update the date above and surface the change in the app before it takes effect.
Questions or requests: support@tetsu.fitness