Darwin Privacy Policy
Effective July 30, 2026 · Applies to the Darwin iOS app
Darwin is built by an athlete, for athletes. The short version: your health data stays on your phone. We collect the minimum needed to run the service, we sell nothing, and we show no ads.
Health data stays on your device
With your permission, Darwin reads workouts, sleep, heart rate, heart rate variability, and resting heart rate from Apple Health. This data is processed entirely on your device to track your plan, compute your readiness score, and display your workout details. Raw health data, workout streams, GPS locations, and sleep records are never uploaded to our servers. Darwin does not write anything to Apple Health.
Your account
Darwin has accounts so your plan survives a lost, broken, or replaced phone. You can sign in two ways:
- Sign in with Apple. We receive a unique identifier and an email address. If you choose Apple's "Hide My Email", we only ever see the relay address — we never learn your real one.
- Email code. We receive the email address you type, and send you a six-digit sign-in code.
We store your email address (or relay address) and an account identifier. We do not ask for your name, phone number, date of birth, or payment details. We never receive your card details: subscriptions are billed by Apple, and we only learn whether your subscription is active.
What leaves your device
Two things, both minimal.
1. Your plan, so it can be restored. When you are signed in, your training plan, your weekly check-in answers, and the adjustments the engine made are backed up to our servers, tied to your account. This is what lets you sign in on a new phone and pick up where you left off. It contains your event, your race date, your sessions, and the summary figures you entered at each check-in (hours slept, how you felt, whether you fueled).
2. A weekly summary, so we can write your digest. When you complete your Sunday Refresh, a small structured summary is sent so we can generate your plain-language weekly digest. That summary contains your adherence percentage and goal status, three flags (low sleep, low feel, whether long sessions were fueled), the adjustments the engine made, your event name, and week number.
What never leaves your device: raw workout files, second-by-second heart rate or heart-rate-variability streams, individual sleep records, GPS routes or any location data, and your profile photo. Those are read from Apple Health, used on your phone, and stay there.
Who processes it
Your account and plan are stored with Supabase (hosted in the United States), protected so that only your own account can read or write your data. The weekly summary is passed to Anthropic's Claude API solely to write your digest text; it is not used to train AI models. Sign-in emails are delivered by Resend. Subscriptions are processed by Apple and their status is managed by RevenueCat, which receives your account identifier and whether you are subscribed — not your email or any health data.
Training decisions are never made by AI. A deterministic planning engine running on your device makes every training-load decision; the AI only puts those decisions into plain words.
What we never do
- No selling or sharing of your data with data brokers or advertisers
- No ads, no third-party analytics or tracking SDKs
- No tracking you across other apps or websites, and no advertising identifiers
- No reading of contacts, photos (except a profile photo you choose, which stays on device), or location
Retention and deletion
Your plan and history are kept while your account exists, so that your training history works.
You can delete everything yourself, at any time: in the app, go to Account → Delete account. That permanently removes your account, your plan, and your training history from our systems immediately. It cannot be undone.
You can also email justin@darwinendurance.com and we will delete every record tied to your account within 7 days. Deleting the app removes all on-device data immediately, but does not delete your account — use the in-app option or email us for that.
Your rights
Depending on where you live, you may have the right to access, correct, export, or delete your personal data, and to object to certain processing. The in-app delete covers deletion instantly; for anything else, email us and we will respond within 30 days. We will never charge you for exercising these rights, and we will not degrade your service for doing so.
Not medical advice
Darwin provides training guidance for healthy recreational athletes. It is not a medical device and its content is not medical advice. Consult a physician before beginning any training program.
Children
Darwin is not intended for anyone under 16. We do not knowingly collect data from children. If you believe a child has created an account, email us and we will delete it.
Beta software
Parts of Darwin are in beta, and beta builds are distributed through Apple TestFlight. Apple's own privacy terms apply to TestFlight itself. This policy may be updated as Darwin grows; material changes will be announced in the app.
Contact
Justin Ramirez · justin@darwinendurance.com