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Terms of Service

Last updated: 29 July 2026

1. Agreement

These Terms of Service (the “Terms”) are an agreement between you and Thomas Bryden, trading as Mast, a sole trader based in the United Kingdom (“Mast”, “we”, “us”), and govern your use of the Mast iOS app and this website (together, the “Service”). By downloading or using the Service you agree to these Terms. If you do not agree, do not use the Service.

Our Privacy Policy explains how we handle your personal data and forms part of these Terms.

2. What Mast does

Mast is a screen-time app. You create commitments - real-world tasks on a schedule - and choose apps to block. At the scheduled time, Mast uses Apple’s Family Controls and Device Activity frameworks to shield your chosen apps until you complete the commitment using the unlock method you configured. Access to Mast’s features requires an active subscription (section 5).

3. Eligibility

You must be at least 13 years old to use the Service. If you are under 18, you may use the Service only with the consent and supervision of a parent or guardian who agrees to these Terms on your behalf. You must be legally capable of entering into a binding contract to purchase a subscription.

4. Your account

You need an account to use Mast. You agree to provide accurate information, keep your sign-in credentials secure, and not share your account. An account is for one person; you are responsible for activity under it. Tell us promptly at contact@tombryden.dev if you suspect unauthorised use.

5. Subscriptions

Mast offers auto-renewing subscriptions under the Mast Plus group:

  • Mast Plus · Yearly - billed once per year.
  • Mast Plus · Weekly - billed once per week.

Both plans include a 7-day free trial for eligible new subscribers.

The price is shown in the App Store in your local currency at the point of purchase. Payment is charged to your Apple Account when you confirm the purchase (or, for a free trial, when the trial ends).

Your subscription renews automatically unless you cancel at least 24 hours before the end of the current period. Your Apple Account is charged for renewal within 24 hours before the current period ends. You can manage or cancel your subscription at any time in your App Store account settings (Settings → your name → Subscriptions); deleting the app does not cancel a subscription. Any unused portion of a free trial is forfeited when you purchase a subscription.

All billing is handled by Apple - we never receive your payment card details and cannot issue refunds for App Store purchases directly. Refund requests are made to Apple at reportaproblem.apple.com and are governed by Apple’s policies and applicable law. Nothing in this section affects your statutory rights.

Restoring purchases links your App Store subscription to the account you are signed in to; restoring on a different Mast account moves the subscription’s entitlement to that account.

6. App blocking - what you're agreeing to

Blocking apps is Mast’s entire purpose, and you configure how strict it is. By using Mast you acknowledge that:

  • Mast will intentionally restrict access to the apps, categories, and websites you select, at the times you schedule.
  • If you choose monk mode, there is no escape hatch: your selected apps stay blocked until you complete the commitment. You choose this deliberately, and we are not obliged to unlock apps early on request.
  • You are responsible for the commitments and blocking rules you set. To the extent permitted by law, we are not liable for consequences of being unable to access a blocked app - for example a missed message, notification, or transaction.
  • Apple’s frameworks do not block core system functions such as making phone calls, including emergency calls. However, you should not rely on any blocked app being available in an emergency.
  • Mast is a productivity tool, not medical, psychological, or therapeutic advice or treatment. We make no guarantee that using Mast will reduce your screen time or improve wellbeing, and no guarantee that blocking will operate uninterrupted or error-free in every circumstance.

7. Acceptable use

You agree not to:

  • bypass, disable, or manipulate Mast’s locking features other than through the unlock methods the app provides, or exploit bugs to do so (if you find one, please report it to us instead);
  • reverse engineer, decompile, or tamper with the Service, except where the law expressly permits it;
  • use the Service unlawfully, infringe others’ rights, or submit content that is unlawful or harmful;
  • interfere with the Service’s operation or attempt to access other users’ data; or
  • resell or redistribute the Service.

8. AI photo verification

Commitments can be verified by photo. Submitted photos are reviewed automatically by an AI model against the prompt you wrote, and are never stored (see the Privacy Policy). Automated review is imperfect and may occasionally approve or reject a photo incorrectly. The fallback you configure for each commitment (such as an escape hatch timer) governs what happens if verification does not go your way, and verification outcomes are final.

9. Your content

You own the content you put into Mast - commitment names, photo-check prompts, cover images, and verification photos. You grant us a limited, non-exclusive licence to host and process that content solely to operate and improve the Service. You are responsible for your content and must have the rights to anything you upload.

10. Licence and intellectual property

We grant you a personal, non-exclusive, non-transferable, revocable licence to use the Mast app on Apple-branded devices that you own or control, as permitted by the App Store terms. The Service, its software, design, and branding are owned by us or our licensors and are protected by intellectual property law. If you send us feedback, we may use it without obligation to you.

11. Third-party services

The Service depends on third parties, including Apple (App Store, billing, and the Screen Time frameworks), Clerk (accounts), Amazon Web Services (hosting), PostHog (analytics), and OpenAI (photo verification). Their availability is outside our control. How they handle personal data is described in the Privacy Policy.

12. Availability and changes to the Service

Mast is designed to work offline-first, but parts of the Service depend on network connectivity and third parties, and we do not guarantee uninterrupted availability. We may update, change, or discontinue features. If we discontinue the Service entirely or make a change that materially reduces what your paid subscription includes, we will give you reasonable notice where practicable, and your remedies with respect to amounts already paid are governed by Apple’s refund policies and applicable law.

13. Termination

You can stop using the Service at any time and delete your account in the app or by emailing us. We may suspend or terminate your access if you materially breach these Terms, if we are required to by law, or if we discontinue the Service. Sections that by their nature should survive termination (including sections 9, 10, 14, 15, and 16) survive it.

14. Disclaimers

Except as expressly set out in these Terms, and to the fullest extent permitted by law, the Service is provided “as is” and “as available”, without warranties of any kind, whether express or implied. If you are a consumer, nothing in these Terms affects your statutory rights - including, in the UK, your rights under the Consumer Rights Act 2015 that digital content be of satisfactory quality, fit for purpose, and as described.

15. Limitation of liability

Nothing in these Terms excludes or limits our liability for death or personal injury caused by our negligence, for fraud or fraudulent misrepresentation, or for anything else that cannot be excluded or limited by law.

Subject to that, we are not liable for loss or damage that is not foreseeable, for loss of profits, business, or data in connection with business use (the Service is for personal use), or for events outside our reasonable control. Our total liability to you in connection with the Service is limited to the greater of (a) the amounts you paid for the Service in the 12 months before the claim arose and (b) £50.

16. Governing law

These Terms are governed by the laws of England and Wales, and the courts of England and Wales have jurisdiction over any dispute - except that if you are a consumer living elsewhere, you keep the protection of any mandatory rules of the law of your country of residence and may bring proceedings in your local courts.

17. Apple app store terms

Because Mast is distributed through Apple’s App Store, the following also apply:

  • These Terms are between you and Mast only - not with Apple. Apple is not responsible for the app or its content.
  • Your licence to the app is limited to use on Apple-branded devices you own or control, per the App Store terms, except that the app may be accessed by other accounts via Family Sharing.
  • Mast, not Apple, is responsible for maintenance and support of the app. Apple has no obligation to provide any support.
  • If the app fails to conform to an applicable warranty, you may notify Apple and Apple will refund the purchase price (if any); to the maximum extent permitted by law, Apple has no other warranty obligation for the app.
  • Mast, not Apple, is responsible for addressing any claims relating to the app, including product liability, regulatory compliance, and consumer protection claims, and for the investigation and resolution of any third-party claim that the app infringes intellectual property rights.
  • You represent that you are not located in a country subject to a U.S. Government embargo or designated a “terrorist supporting” country, and that you are not on any U.S. Government list of prohibited or restricted parties.
  • You must comply with applicable third-party terms (such as your wireless data agreement) when using the app.
  • Apple and its subsidiaries are third-party beneficiaries of these Terms and, upon your acceptance, may enforce them against you.

18. Changes to these Terms

We may update these Terms from time to time. If we make material changes we will give you notice, such as in the app or by email, before they take effect. Continued use of the Service after changes take effect means the updated Terms apply. If you do not agree to a change, stop using the Service and cancel your subscription in your App Store settings.

Questions about these Terms? Email contact@tombryden.dev.