Compound privacy policy
Compound is a strength-training app. This policy says what it does with your information, in plain words, because the app's whole idea is that nothing is on trust, including this.
The short version: your training lives on your phone first, and syncs to your account so it follows you. The Compound app has no advertising identifiers. It does not record how you use it unless you turn usage sharing on. Screen recording is separate: it runs only for the account that builds the app, and text fields are masked. A crash sends an error report, Report a problem sends a picture only when you choose to, and a note you choose to send about how the app is working is stored with your account. Beyond your account's copy, what leaves your device is listed below: the app's own update checks, sign-in emails, the store's subscription check, crash reports, usage if you turn sharing on, and files or reports you choose to send yourself. Building a program, asking why one weight is what it is, and rewriting a note after a session also send the engine's training facts, with no name and no email, to Anthropic to write the explanations. A note you wrote on an exercise is not included.
Who is responsible
Compound is published by Compound Training Ltd, a company registered in Scotland (company number SC903620), whose registered office is 5 South Charlotte Street, Edinburgh EH2 4AN. Compound Training Ltd is the controller of the personal data this policy describes. Questions about this policy or your data: [email protected].
Your account
Compound needs an account, made with Google, Apple or an email code. We never see or store a password. The account holds an id and your email address. If you sign in with Google or Apple, they also send your name and a picture link; we discard both as they arrive and keep only the email. With Apple's Hide My Email, the email we hold is the private address Apple gives us. You must be 18 or over. Before you sign up, the app asks your date of birth once, checks it on your phone and keeps only that you confirmed you were 18 or over, and the date you did. Your date of birth is never stored or sent to us.
What Compound stores, and where
Your training is saved on your phone first, so the app works without a connection. On your phone, in the app's own storage:
- Your program and position in it: the program you chose or built, which week and session you're on, your training maxes, edits you've made, today's swaps and settings.
- Your history: every session you finish: the exercises, the weight, reps and effort of each set, and when each set was logged.
- Your gyms: the equipment you've said each gym has, and swaps you chose there.
- Your settings: units, training days, session length, appearance, notes on exercises, and, if you chose to enter them, one bodyweight and sex for the relative-strength reading.
- Your own lifts: lifts you create or import, with their name, equipment and body area.
- Suggestions: changes the app proposed, and whether you accepted them.
- Backups: up to three rotating copies of the above, kept in the app's own storage so a bad save can't lose your history. They are deleted with the app.
Your account keeps a copy of your settings, gyms, programs, history and suggestions. It also keeps the lifts you create or import (name, equipment and body area), so they appear on every device you sign in on. Only you can see them, and they are deleted when you delete your account. Your account's copy is stored with Supabase in London, United Kingdom, encrypted in transit and at rest. It is not end-to-end encrypted: our systems can read it, because they run the same training rules on it that your phone does. Nobody at Compound reads it by hand unless you ask us to help with something, and when we do we tell you in the same conversation what was read. Your sign-in events are kept for 30 days.
What leaves your device
- Your account's copy. With an account, a copy of your training, settings, gyms, programs, history, your own lifts and the suggestions the app made you is sent to the account's store, described above. Your bodyweight and sex are not part of it by default.
- Program explanations. When a program is built, when you ask why a weight is what it is, and when a note is rewritten after a session, the app sends the engine's training facts to Anthropic to write the explanations: the goal, the split, the blocks, the training maxes, the prescribed loads, and the library's how-to line for a lift. Your name, your email, and a note you wrote on an exercise are not in that. The notes come back and stay on your phone.
- Sign-in emails. To send you a sign-in link and code, your email address and that message go through Resend (see Where it is processed).
- Update checks. When the app opens it may ask Expo's update service (expo.dev, run by Expo, Inc.) whether a newer version of the app's code is available, and download it. That request carries the technical information any such request carries: your device's IP address, device model and operating system, the app version and the update channel. It carries nothing about your training. Expo's own policy governs their handling of it: https://expo.dev/privacy.
- Subscription checks. If you start a trial or subscribe to Pro, the app asks the App Store or Google Play whether your subscription is active, and the store handles any purchase under its own terms. We never see your card details, and nothing about your training is sent. Our server counts each change to your subscription (a start, renewal, cancellation, expiry, refund or billing problem) with PostHog in the European Union, with the store, the plan, the price and the currency, and not your account or your email.
- Files you share. You can save a backup file or share one to another app (You → Backup and restore). Where it goes is your choice and the receiving app's policy applies. Compound does not send it anywhere on its own.
- The app stores. Google Play and the App Store collect their own install and crash information under their own policies. Compound also sends its own crash reports, described below.
- Your phone’s own backup. Android and iOS may include Compound’s data in the device backup you have set up (Google or iCloud), encrypted by your phone and governed by Google’s or Apple’s policy. That is how your history comes back to a new phone. Compound never sees that copy.
Crash reports. When a screen fails, Compound sends the error, the app version and the platform to PostHog, on its servers in the European Union. In app version 1.0.1 and later, a crash report is not tied to your account, your account id or your email, whether or not you are signed in, and it is sent separately from Share usage. It does not include your training, your history or your maxes. We use it to fix the fault. Because a crash report in app version 1.0.1 and later carries nothing that links it to you, we cannot find or delete one of those by account. We keep crash reports only as long as we need them to fix the fault.
Problem reports you choose to send. "Report a problem" (on You, and in a session's menu) sends a picture of the screen you were on, a line you may write, the app version, the platform and the name of that screen. It does not include your training history, your maxes or your backup. The picture may show the weights on that screen, and you see it before you press Send. Nothing is sent until you do. It is stored with your account at Supabase in London, in a private store only we can read. We keep a report until the fault is fixed, and no longer than six months, and it is removed when you delete your account.
A note you choose to send. After five sessions with a set logged, the app may ask once how Compound is working for you. If you write a note and press Send, we store that text with your account at Supabase in London, with the app version, the platform, and how many sessions you had logged. Nothing is sent until you do. Only we can read it. We keep it while your account exists, and it is removed when you delete your account. Choosing Not now stores only that we have already asked, with no note, and that is removed with the account too. The words are not sent as a usage event.
There are no advertising identifiers. Usage is shared only if you turn it on (below). We never sell your data or share it with advertisers.
What we do with it
We use it to run the app for you: to build your sessions, keep your history on every phone you sign in on, and show you what changed and why. Writing a program's explanations, an answer about one weight, or a rewritten note after a session sends the engine's training facts to Anthropic, as part of that, and not your name, your email, or a note you wrote. We do not use it to profile you for marketing.
Two things you choose
Share usage (it arrives in the next app update; until then the app sends no usage events, and it will be off until you turn it on): which screens and options get used. Those app usage events are sent without your account or your training numbers. If Today and Program disagree about the session you are on, that event can include the program id, the week, and the session's place in the week, plus the app version. It is sent only while Share usage is on, and only when the screens disagree. It does not include a session name, a weight or a rep count. The other events tell us what the app's pages do. They are not anonymous in the strict sense, since a device could in principle be told apart, which is why this is off until you choose it.
Program explanations, and Share usage. Writing a program's explanations, asking why a weight is what it is, and rewriting a note after a session do not send a usage event unless Share usage is on. When it is on, one event goes to PostHog in the European Union for each of those. It is not tied to your account, your account id or your email. It carries the model, the token counts, the cost, how long the read took, a trace id for that read, which of the three it was, and whether the account is free, Pro or in the trial. If a note failed its check, a second event carries the check's code, where it sits, and that program's id, not the words. Neither event includes what was written, what was asked, or a training number. When Share usage is off, neither event is sent.
Help improve the programs (not available yet; when it arrives it will be off until you turn it on, and asked once you have some history): your training data, with your account removed, used to check what the programs prescribe against what lifters actually do and achieve. Never for marketing. Turning it off deletes what was shared, within 30 days.
Your bodyweight and sex
If you gave them, they stay on your phone and are not part of your account's copy. They leave your phone only when you link a coach and agree to share them; that asks you plainly, and you can withdraw it.
A coach, if you choose one
Linking to a coach lets them read your history, programs and the settings the training rules need (units and training days; your bodyweight only if you agree to share it when you link), and write changes to your program in their name. It gives you nothing of theirs. You can end the link at any time; your history stays yours.
Notifications
If you allow notifications, Compound schedules one local reminder when a rest timer ends. It is created and delivered on your device; nothing is sent to a notification service.
Health data
Compound does not read from or write to Apple Health, Google Fit or Health Connect. If a future version offers that, it will ask first, and this policy will be updated before it does.
Importing from other apps
You can import your training from a CSV file, from Strong, Hevy or a spreadsheet. The file is read on your device. Any lifts in it that are not in Compound's library are saved with your account once you confirm the name, like lifts you create yourself.
Deleting, and taking it with you
- See it: everything the app holds is on screen: your history, program, gyms and settings.
- Export it: You → Backup and restore saves a complete copy as a file you own.
- Delete it: delete your account from You and your data is removed from our systems no later than 30 days afterwards. Supabase keeps daily backups of the database for seven days, so your data is gone from them within seven days of deleting your account. Deleting the app deletes what is on that phone, including the app's own backups.
Children
Compound is for adults: it is listed for people aged 18 and over, and an account needs you to be 18 or over. It is not directed at children, and we do not knowingly collect information from them. If you think someone under 18 has an account, email us and we will delete it.
Your rights, and the legal basis
We process your account and training data to provide the service you asked for (contract). Crash reports and problem reports are sent so we can fix faults (legitimate interest). A feedback note is sent only if you write one and press Send (consent), so we can read how the app is working for you. Usage sharing and Help improve the programs run on your consent, which you can withdraw in You → Data when each switch is in the app. Bodyweight and sex are shared only on your explicit consent. We keep your data while your account exists, and until it is removed after you delete it, no later than 30 days afterwards; problem reports for up to six months; a feedback note while your account exists, removed when you delete the account; crash reports until we no longer need them to fix the fault; shared usage for 12 months; Help improve data while the toggle is on and for 30 days after; sign-in events for 30 days. You can ask for a copy of your data in a form you can take elsewhere, have it corrected, restricted or deleted, or object to a use, from You or by writing to [email protected]. If you are unhappy with how we handle it, you can complain to the Information Commissioner's Office (ico.org.uk).
Visits to this website
This website (not the app) counts visits with Cloudflare Web Analytics, run by Cloudflare, Inc., which hosts the site. It sets no cookies, stores nothing on your device and doesn't follow you to other sites. It tells us how many people visited, which pages, from which country and on what kind of device, and never who you are. Cloudflare's own policy governs it: https://www.cloudflare.com/privacypolicy/.
Where it is processed
Cloudflare (this website, its visit counts and the Coached sign-in) is a processor based in the United States. Supabase keeps your account's copy, the problem reports you send, and a feedback note you choose to send, in London, United Kingdom, as our processor under its data processing agreement. PostHog (PostHog, Inc.) receives crash reports, subscription records, and the usage and explanation events above when Share usage is on, on its European Union servers in Frankfurt, as our processor under its data processing agreement. Crash reports from app version 1.0.1 and later carry no account id, as do usage events and explanation events; usage and explanation events are not sent while Share usage is off. Session recording is sent to the same place, and only for the account that builds the app: text fields, images and system views are masked, and taps, logs and network data are not captured. When Share usage is on, a screen check can also send the program id, the week and the session's place in the week if the screens disagree, and not a session name, a weight or a rep count. None of them carries your email. Resend (Resend, Inc., USA) sends sign-in emails from its EU region and handles your email address and the sign-in message; it is our processor under its data processing agreement, is certified under the EU–US Data Privacy Framework and its UK Extension, and the agreement also carries the EU Standard Contractual Clauses and the UK Addendum. Its sending logs are kept for 30 days. Anthropic (Anthropic, PBC, USA) writes a program's explanations, the answer when you ask why a weight is what it is, and a rewritten note after a session. It receives the engine's training facts — the goal, the split, the blocks, the training maxes, the prescribed loads, and the library's how-to line — and not your name, your email, or a note you wrote on an exercise. It is our processor. Nothing you log in the app is sent to Cloudflare.
Changes
If this policy changes in a way that matters to you, the app will say so before the change applies, the version date at the top will move, and the app's "What's new" will say so.