Terms of service
Last updated: 17 September 2026. These terms cover the Foil coaching app during its private beta. They are short because the product is, and because a document nobody reads is not an agreement.
Who operates Foil
Alexander Kapp, Rehgasse 21, Innsbruck, Austria. Write to support@foil.fit about anything on this page.
What Foil is
Foil is adaptive endurance coaching software, in a private beta that you join by invitation. It reads your training activities and your daily readiness figures — sleep, heart rate variability, resting heart rate — compares the sessions that were planned with what actually happened, adapts the plan, and explains its reasoning in a conversation you can argue with.
It is not medical advice
Foil is not a clinician and does not diagnose anything. It reads numbers from a watch and a strap and reasons about training load; it cannot see you, examine you, or know what those numbers mean for your health. If you are unwell, injured or in pain, see a doctor or a physiotherapist, and nothing the coach says is a reason not to. Endurance training carries a real risk of injury. The coach proposes; you decide what you actually do, and that decision is yours.
The coach can be wrong
A deterministic engine does the arithmetic — volume progression, readiness flags, planned against actual — and a language model reasons about what the engine flags and puts it into words. The model can still be mistaken: it can misread a situation, weigh the wrong thing, or be confidently off. Arguing with it is the design, not a workaround. Use your own judgement, especially on the days it matters most.
Who may hold an account
You must be 18 or over. One account per person, opened with an invitation, and it is personal: it is not shared, lent or handed on. The coach’s reasoning about your body only makes sense if the body it reasons about is yours.
What “beta” means here
Foil is free for now. There is no uptime promise, and features may change or be withdrawn while the product finds its shape. Either side may end the account: you from Settings, Foil by telling you. If Foil has to close your account, or close the beta, it will say so rather than going quiet.
Your data stays yours
Your activities, readings, conversation and plan are yours. Foil takes only the licence it needs to run the service for you: to store the data, send the relevant parts to the providers that generate replies, and show it back to you. Foil does not sell your data and does not use it to train models. The privacy notice says what is stored, where it goes and why.
Connected sources
The grants that let Foil read from intervals.icu and Whoop belong to you. You give them at those providers and you revoke them there. What Foil stores is a token that exercises the grant, not the grant itself: deleting Foil’s copy means Foil can no longer read, and revoking at the provider is what actually ends the access.
Acceptable use
Do not attack the service, probe it, or scrape it. Do not resell it or offer it on to others. Do not use your account to coach other people’s accounts, or other people through yours. The beta is small enough that any of these gets noticed and ends the account.
Ending it
Deletion is self-serve from Settings. It is scheduled rather than instant: the account is deleted seven days after you ask, and until then one button undoes it, leaving nothing changed. Coaching carries on during those seven days. Before you delete, Settings can also give you a full copy of everything Foil holds about the account, as one file.
Liability
During the beta, Foil is provided as it is, and Foil’s liability is limited to what the law allows. Nothing in these terms limits liability for death or personal injury caused by negligence, or for anything else that cannot be limited under Austrian law.
Changes
A new version of these terms carries a new date at the top. Material changes are emailed to the address on your account before they take effect, rather than edited in silently.
Governing law
Austrian law applies, and the courts of Innsbruck have jurisdiction. If you are a consumer, this does not displace your right to bring or face a claim in the courts of your own country.