4ft3rh0urs

Terms of Service

Onyx · Last updated 26 September 2026

These terms apply to your use of the Onyx workout tracker ("the app"), developed by 4ft3rh0urs in the Netherlands. By creating an account or using the app, you agree to these terms. If you don't agree, please don't use the app.

1. The service

Onyx lets you log workouts, save routines, track your body weight and follow your progress, with your data backed up to your account.

2. Your account

3. Your data

Everything you log stays yours. You give us permission to store and sync it only as needed to run the app, as described in the privacy policy.

4. Not medical advice

Onyx is a logbook, not a coach or a medical device. Calorie estimates, records and other numbers are approximations. Exercise at your own risk, and check with a doctor before starting a new training program, especially if you have a health condition or injury.

5. Acceptable use

Don't use the app for anything illegal, try to access other people's data, or disrupt the service.

6. Availability and changes

We do our best to keep the app working and your data safe, but we can't guarantee the app will always be available or free of errors. We may change, improve or stop features. If we plan to shut the service down, we'll let you know in advance so you can save your data.

7. Liability

The app is provided "as is". To the extent the law allows, 4ft3rh0urs is not liable for injuries from exercise, indirect damage or lost data resulting from use of the app. Nothing in these terms limits liability that can't be limited by law, for example for intent or gross negligence.

8. Ending your use

You can stop using the app and delete your account at any time in Settings → Delete account. We may suspend or close accounts that break these terms.

9. Changes to these terms

If we change these terms, we'll update the date at the top. For important changes, we'll let you know in the app. If you keep using the app after a change, the new terms apply.

10. Applicable law

These terms are governed by Dutch law. Disputes go to the competent court in the Netherlands, unless the law gives you the right to go to a court in your own country.

11. Contact

4ft3rh0urs, the Netherlands · optroot.store@outlook.com