ONYXThese terms govern your use of the Onyx iOS and watchOS app, made by TheMillerBrand. By using Onyx, you agree to them. If you don't agree, don't use the app. They are also Onyx's end-user licence agreement (EULA) on the App Store.
What Onyx is
Onyx is a personal health, fitness, and nutrition app for iPhone and Apple Watch. It reads metrics from Apple Health, computes a daily recovery score, generates training and nutrition guidance, reads imported bloodwork, and offers an AI coach that reasons against your current state. It is not a medical device, not a diagnostic tool, and not a replacement for a clinician.
Your account
There is no Onyx account. Your data lives on your iPhone. If you're signed in to iCloud, Onyx syncs your settings and preferences to your own private iCloud database using Apple's CloudKit; we can't read it, and we don't hold a copy. Your health data is not stored in iCloud. Apple's In-App Purchase system handles payment; we never see your payment details.
Apple Health permissions
Onyx asks permission to read and write specific Apple Health metrics, in two stages: a core set at setup and a smaller second request the first time you open the Body tab. You grant or revoke each one in iOS Settings. Onyx can't function as designed without read access, but you decide what's shared, and the app degrades honestly rather than inventing numbers it can't measure.
Onyx Pro
Pro is offered as a monthly subscription, an annual subscription, or a one-time lifetime purchase. Prices are shown in the app and may change. All transactions go through Apple's In-App Purchase system; Apple's terms govern purchase, refund, and renewal.
Subscriptions auto-renew unless you turn off auto-renewal at least 24 hours before the period ends. Manage or cancel in iOS Settings → your name → Subscriptions.
Refunds are handled by Apple. Request one through Apple's standard process at reportaproblem.apple.com.
Grandfathered Pro: anyone who had a version of Onyx installed before v2.0 receives Pro for life at no cost. This is a courtesy and may be withdrawn if abused, for example by creating multiple installs to game it.
Acceptable use
Don't try to break the app, reverse engineer it, or use it for anything unlawful. Don't use Coach to ask for help with anything illegal or harmful, or anything that would violate Anthropic's usage policies.
Coach and other AI features
Coach, food photo parsing, menu reading, bloodwork extraction, and the written narratives are powered by an AI model and may produce inaccurate or incomplete results. Treat them as a thoughtful starting point, not a final answer. Onyx asks your permission before it sends anything to its AI provider, and you can turn AI features off at any time.
Bloodwork extraction in particular reads numbers off an image. Check the values against your original lab report before acting on anything. Onyx shows you the extracted panel for review before it saves, and that review step exists for a reason.
No medical advice
Nothing in Onyx is medical advice. The recovery score, illness early-warning, heart-rhythm notifications surfaced from Apple Health, training recommendations, bloodwork readings, and Coach replies are signal, not diagnosis and not prescription. If something feels wrong, see a clinician. We are not liable for decisions you make based on Onyx's output. See the Medical Disclaimer for the longer version.
Intellectual property
The Onyx app, its design, copy, and underlying code are owned by TheMillerBrand. You get a personal, non-transferable licence to use it on devices you own. You don't get to copy it, redistribute it, or build a competing product from it.
Third-party services
Onyx works with Apple Health, Apple CloudKit, Apple In-App Purchase, Anthropic (for Coach and every other AI feature), Railway (which hosts Onyx's server), OpenFoodFacts (for barcode scans), and Meta (to measure Onyx's own ads). Each has its own terms. We're not responsible for outages, errors, or terms changes from any third party. The Privacy Policy explains what each one receives.
Disclaimer of warranties
Onyx is provided "as is." We don't warrant that it will be uninterrupted, error-free, or fit for any particular purpose. To the extent permitted by law, we disclaim all implied warranties.
Limitation of liability
To the extent permitted by law, TheMillerBrand is not liable for indirect, incidental, special, or consequential damages arising from your use of Onyx. Our total liability for any claim is limited to the amount you paid us in the 12 months before the claim, and zero if you never paid.
Termination
You can stop using Onyx any time by deleting it. Deleting the app does not remove settings already synced to your iCloud account; use Delete account & data in Onyx first if you want them gone. We can suspend or terminate access if you violate these terms. Termination doesn't refund subscriptions.
Governing law
These terms are governed by the laws of the United States and the State of New York, without regard to conflict-of-laws principles. Disputes will be resolved in the state or federal courts of New York County, New York.
Changes to these terms
We may update these terms. Material changes will be reflected here with a new date at the top. Continued use means you accept the new version.