Muscle OS

Muscle OS

Terms of Service

Effective May 5, 2026 · Last updated May 5, 2026

These Terms of Service (the “Terms”) form a binding agreement between you and ALEX DEVELOPMENT (“we”, “us”, “our”). They govern your use of the Muscle OS mobile application and the website at https://muscle-os.app (together, the “Service”). They also serve as the End User License Agreement (EULA) required by the App Store and Google Play. Please read them carefully — by downloading, installing, accessing or using the Service you accept the Terms in full.

1. Acceptance of these Terms

By creating an account or using any part of the Service you confirm that you have read, understood and agreed to be bound by these Terms and by our Privacy Policy. If you do not agree, do not use the Service.

2. Eligibility and age

The Service is intended for use by people aged 16 or older. If you are between 16 and the age of legal majority in your country, you must have your parent or legal guardian read and accept these Terms together with you. We do not knowingly allow children under 16 to use the Service or to create an account.

3. The agreement is with us, not Apple or Google

These Terms are between you and ALEX DEVELOPMENT only, and not with Apple Inc. or Google LLC. Apple and Google are not responsible for the Service or for any claims relating to it. To the extent that these Terms grant Apple or Google any third-party beneficiary rights — for example because they are included in Apple’s minimum EULA terms — those rights take effect, and Apple and Google may rely on them. We are solely responsible for providing support, for any product warranties to the extent not effectively disclaimed below, and for handling claims that the Service infringes third-party intellectual-property rights.

4. Your account

  • You are responsible for keeping your sign-in credentials confidential.
  • You are responsible for all activity carried out through your account.
  • You must give us accurate information when you sign up and keep it up to date.
  • You can delete your account at any time from inside the App. Account deletion is described in the Privacy Policy.

5. License to use the Service

Subject to your compliance with these Terms, we grant you a limited, personal, non-exclusive, non-transferable, non-sublicensable, revocable license to download and use the App on a device you own or control, and to access the Site, for your own personal, non-commercial use. The license is governed by the usage rules of the App Store and Google Play, including any geographic limitations.

6. Subscription terms (Muscle OS Plus)

The App is free to download. Some features require an active Muscle OS Plus subscription. The terms below apply if you purchase one.

Auto-renewable subscription disclosure

  • Plans: $1.99/month (monthly) or $9.99/year (annual). The annual plan works out to $0.83 per month.
  • New users may be entitled to a 7-day free trial of Muscle OS Plus. The trial automatically converts into a paid subscription unless you cancel at least 24 hours before it ends.
  • Payment will be charged to your Apple ID or Google Play account at confirmation of purchase.
  • Subscriptions automatically renew at the end of each billing period unless auto-renew is turned off at least 24 hours before the end of the current period.
  • Your account will be charged for renewal within 24 hours prior to the end of the current period at the price of the selected plan.
  • You can manage your subscription and turn off auto-renewal at any time, from your Apple ID Account Settings (iOS) or your Google Play subscriptions page (Android).
  • Any unused portion of a free trial is forfeited when you purchase a subscription, where applicable.

6.1 Price changes

We may change subscription prices. If we do, the new price will not apply to your current billing period. We will give you advance notice and an opportunity to cancel before the new price takes effect, in line with App Store and Google Play rules.

6.2 EU right of withdrawal (14-day cooling-off period)

If you live in the European Union, the EEA, the United Kingdom, or another jurisdiction granting an equivalent right, you have the right to withdraw from a subscription within 14 days of purchase, without giving a reason. To exercise it, contact [email protected] within the period.

By starting to use Muscle OS Plus features (for example, by unlocking a paid feature) before the end of the 14-day period, you expressly request that we begin performing the service immediately and you acknowledge that you will lose your right of withdrawal once the service has been fully performed. If the service has only been partially performed when you withdraw, you must pay an amount proportional to what has been provided up to the time of withdrawal.

6.3 Refunds

Because subscriptions are sold and processed by Apple and Google, all refund requests must be addressed to them directly:

Where mandatory consumer-protection law in your country grants you a further refund right against us, we will of course honour it.

7. Acceptable use

You agree not to:

  • Use the Service for any unlawful purpose or in breach of any applicable law;
  • Reverse-engineer, decompile, disassemble or attempt to extract source code from the App, except where the law expressly allows it;
  • Resell, sub-license or commercially redistribute access to the Service;
  • Use any automated means (scrapers, bots) to access the Service or to extract its data;
  • Interfere with the operation, security or integrity of the Service, or attempt to circumvent its access controls;
  • Use the Service to harass, defame or harm others.

8. Your content

Programs, sessions, body-weight entries and notes you record are your content. You keep all rights in it. You grant us a worldwide, royalty-free, non-exclusive licence to host, store, transmit and display that content on your own devices and to other accounts you authorise — strictly for the purpose of providing the Service to you. The licence ends when the content is deleted or your account is closed, except for backup copies kept for the limited retention period described in the Privacy Policy.

9. Health and fitness disclaimer

The Service is a tool for self-tracking and is not a medical device. It does not provide medical advice, diagnosis or treatment. Information shown in the Service — including suggested loads, volumes, programs and progress estimates — is for general informational purposes only.

Resistance training carries inherent risk of injury. You should consult a qualified physician or other healthcare professional before starting any exercise program, especially if you have a medical condition or are pregnant. By using the Service you acknowledge that you do so at your own risk and that you are responsible for your own physical safety. We are not liable for any injury, loss or damage resulting from your use of the Service or from following information it provides.

10. Intellectual property

The Service, including its source code, design, branding, copy, icons and logos, is owned by ALEX DEVELOPMENT or licensed to us, and is protected by copyright, trademark and other intellectual-property laws. Except for the limited license in section 5, nothing in these Terms transfers any of those rights to you.

11. Third-party services

The Service relies on third-party platforms, including Apple App Store, Google Play, Apple Health, Google Health Connect, Sign in with Apple, Sign in with Google, RevenueCat and our hosting providers. Their own terms and privacy notices apply to their services. We are not responsible for the content or practices of those third parties.

12. Warranties and disclaimers

To the maximum extent permitted by applicable law, the Service is provided “as is” and “as available”, without warranty of any kind, whether express, implied or statutory, including without limitation warranties of merchantability, fitness for a particular purpose, accuracy, reliability or non-infringement.

Nothing in these Terms excludes or limits any warranty or right that cannot be excluded or limited under the law applicable to you, including the statutory consumer guarantees under French and EU law (notably the legal guarantee of conformity provided by Articles L. 217-3 and following of the French Code de la consommation).

13. Limitation of liability

To the maximum extent permitted by applicable law, ALEX DEVELOPMENT will not be liable for any indirect, incidental, special, consequential or punitive damages, or for any loss of profits, revenues, data or goodwill, arising from or related to your use of the Service.

Our total aggregate liability arising out of or in connection with these Terms is limited to the greater of (a) the total amount you have paid to us for the Service in the twelve (12) months preceding the event giving rise to the claim, or (b) fifty euros (€50).

Nothing in these Terms limits or excludes our liability for fraud, gross negligence, intentional misconduct, death or personal injury caused by our negligence, or for any other liability that cannot be limited or excluded under applicable law.

14. Indemnification

You agree to defend, indemnify and hold harmless ALEX DEVELOPMENT and its officers, employees and agents from any claim, demand, loss, liability or expense (including reasonable lawyers’ fees) arising from your breach of these Terms, your misuse of the Service or your violation of any law or third-party right.

15. Termination

You may stop using the Service and delete your account at any time. We may suspend or terminate your access if you breach these Terms or if we are required to do so by law. On termination, the licence in section 5 ends immediately. Sections that by their nature should survive termination (sections 9 to 17) will continue to apply.

16. Governing law and disputes

These Terms are governed by the laws of France, without regard to its conflict-of-law rules. Disputes will be brought before the courts of the publisher’s registered office, except that consumers may also bring proceedings in the courts of their place of residence, as provided by the Brussels I bis Regulation.

Before going to court, you may try to resolve the dispute amicably by emailing [email protected]. Consumers may also use the European Commission’s Online Dispute Resolution platform at ec.europa.eu/consumers/odr or refer the dispute to a French consumer mediator.

17. Changes, severability, entire agreement

  • Changes. We may update these Terms. Material changes will be communicated through the App or by email at least 30 days before they take effect; continued use of the Service after that period constitutes acceptance.
  • Severability. If any provision of these Terms is found unenforceable, the remaining provisions stay in force.
  • Assignment. You may not assign these Terms without our prior written consent. We may assign them to an affiliate or to a successor in connection with a corporate transaction.
  • Entire agreement. These Terms, together with the Privacy Policy and the Legal Notice, are the entire agreement between you and ALEX DEVELOPMENT regarding the Service.

18. Contact

Questions about these Terms? Write to us at [email protected] or by post at the address listed in our Legal Notice.