Privacy Policy
Compound is a workout log for iPhone and Apple Watch, made by Sean Arnett. This page explains what the app collects, why, and what you can do about it.
The short version
- No ads, ever. No tracking. We don't sell or share your data with advertisers or data brokers.
- Your training data is used only to run the app for you and to back it up to your account.
- You can delete your account and all of its data from inside the app at any time.
What we collect
- Account: your name and email address from Sign in with Apple or Google, and an account ID. If you use Apple's "Hide My Email", we only see the relay address.
- Your training: workouts, sets, plans, templates, notes, recovery sessions, body weight, and your settings and setup answers.
- Apple Health (only if you turn it on): with your permission, Compound can read body weight, heart rate variability, resting heart rate, sleep, active energy, workouts from other apps, body measurements (body fat, lean mass, BMI) and nutrition (calories, protein, carbs, fat). It can also save the workouts you finish in Compound to Apple Health. You choose which of these to allow in the Health app, and you can change that at any time.
- Purchases: subscriptions are handled entirely by Apple. We never see your payment details. The app only learns which plan you have.
We don't collect your location, contacts, photos, or browsing activity, and we don't use any analytics or advertising tools.
How it's used
- To show your training, progress and records, and to run your plans.
- To back up your data so it comes back if you change or reinstall your phone.
- AI Coach (Compound Pro): the AI Coach works with an AI service you already use: ChatGPT (made by OpenAI), Claude (made by Anthropic) or Gemini (made by Google). When you tap Send my week, Compound builds a text summary on your phone and, the first time (and again if you switch AI services), shows you exactly what it contains and who you're giving it to, and asks your permission. If you agree, Compound copies the summary to your clipboard; you paste it into the AI service yourself.
- What the summary can include: your workouts, sets, runs and other sessions with dates; your plan and what you completed or skipped; your coach setup answers and anything you added under "Tell your coach more" (training history, past sports, areas to be careful with, equipment); and, only if you allowed them in Apple Health, your body weight and body fat, food (calories, protein, carbs, fat) and the recovery sessions you timed in Compound.
- What it never includes: your name, email address or account.
- Who receives it: only the AI service you paste it into. Compound never sends it to any AI service itself. A copy of each summary you copy is kept in your private Compound backup, like the rest of your training.
- How it's shared: Compound has no connection to these companies. It makes no network requests to them, holds no API keys, and has no agreement with them. You move the text yourself, by pasting it into their app or website under your own account with them.
- Protection: we only name AI services whose published privacy policies protect personal data at least as well as this policy does: they say what they collect, use it to provide their service to you, don't sell it, and let you delete it. Once you paste the summary, that company's policy and your settings with them apply: OpenAI, Anthropic, Google. If you'd rather your data not be used to improve their models, you can turn that off in your settings with each of them.
- You can turn this off any time in the app (AI Coach → Sharing with your AI → Turn off). Compound will ask again before the next copy.
Health data is never used for advertising or marketing, and never sold.
Where it's stored
Your data is stored on your iPhone and backed up to your private account on Google Firebase (Google Cloud), which we use to run the backup. Each account's data can only be read by that signed-in account. Crash reports, if you choose to share them with developers, come through Apple and don't identify you.
Deleting your data
In the app: Settings → Account & Backup → Delete Account. This permanently deletes your account and your backed-up data from our servers. It doesn't remove what you've already saved to Apple Health; you can manage that in the Health app. Canceling a subscription is done in your Apple ID settings (Settings → Subscriptions); deleting your account doesn't cancel it.
Children
Compound isn't directed at children under 13, and we don't knowingly collect their data.
Changes
If this policy changes, we'll update this page and the date above.
Contact
Questions or requests: seanarnett@me.com