Privacy Policy

Rust (com.rustfitness.app) — Effective / Last updated: August 2026

This Privacy Policy explains what information Rust ("the app," "we," "us") collects when you use the app, how it's used, and the choices you have. Rust is a personal workout-tracking app. We built it to help you train — not to build a profile on you or sell your data.

Information We Collect

We collect only what's needed to run your account and your training data:

Account information — the email address and password you sign up with, and an optional display name. Authentication is handled by our backend provider, Supabase; we never see or store your password in plain text.
Workout data — the exercises, sets, reps, weights, and workout durations you log; calculated stats derived from that data, such as estimated one-rep max, calorie estimates, and progress trends.
Profile and preferences — body weight (if you enter it), training goals, equipment you've told the app you have access to, and challenge/history data you create inside the app.
AI coach conversations — if you use the in-app AI coach, we store the messages you send it and the coach's replies, so your conversation history is there the next time you open it. The coach also extracts and stores specific facts you tell it that are useful for future coaching — for example an injury you mention, a training preference, a goal, or equipment details — so it can recall them later without you repeating yourself.
Readiness check-ins — if you answer the optional pre-workout readiness prompt, we store your sleep, energy, and soreness ratings and any sore body areas you specify, to give the coach better context for that session.
Voice input (optional) — if you use the microphone / tap-to-talk button to talk to the coach, speech-to-text conversion is performed by your device's or browser's built-in speech recognition (for example, Chrome's or Android's native speech service). We only receive and store the resulting text, not raw audio recordings of your voice.

About the AI coach, specifically

Rust includes an optional AI coaching feature (available to subscribers) that gives you personalized training advice. To do this, when you message the coach we send the following to Anthropic (maker of the Claude AI models, our AI provider) so it can generate a response: your message and recent conversation history, your current and recent workout data (exercises, weights, reps, sets), profile details you've provided (goal, experience level, body weight, equipment), and any readiness check-in you completed. Anthropic processes this solely to generate the coach's reply and does not use it to train their models under our agreement with them.

If you tap "Listen" to have a coach reply read aloud, or pick one of the six coach voice personas, the coach's reply text (not your own messages) is sent to ElevenLabs, our voice-synthesis provider, to generate the audio.

You can clear your AI coach conversation history at any time from within the chat (the "Clear" button) — this deletes your stored coach messages. Facts the coach has remembered about you are removed when you delete your account (see "Your Choices" below).

How We Use Your Information

To create and secure your account and sync your data across your devices.
To generate the stats, trends, and recommendations you see in the app.
To power the AI coach's responses and let it remember relevant context about your training between conversations.
To operate, maintain, and improve the app.

We do not use your data for advertising, and the app does not contain ad SDKs or third-party trackers.

How Your Information Is Stored

Your data is stored using Supabase, our database and authentication provider, which hosts data on secured cloud infrastructure. We take reasonable technical and organizational measures to protect your information, but no method of transmission or storage is 100% secure.

Sharing Your Information

We do not sell your personal data, workout data, or AI coach conversations to third parties, ever. We only share information with the service providers who help us run the app, under obligations to protect your data and only for the purposes described here:

Supabase — authentication and data storage for your account, workouts, and coach conversation history.
Anthropic — processes your coach conversation and relevant workout context to generate AI coaching responses, only when you use the AI coach feature.
ElevenLabs — converts the coach's reply text to speech audio, only when you use the "Listen" / voice-persona feature.

We may also share information when required by law, or to protect the rights, safety, or property of Rust, our users, or others.

Wearable & Health App Data (Apple Health / Health Connect)

If you connect a wearable, Rust reads today's steps, most recent heart rate reading, and today's active calories from Apple Health (iOS) or Health Connect (Android) — whichever platform your device, such as a Garmin or Apple Watch, syncs into. Rust never connects to Garmin's or Apple's servers directly; it only reads from the platform health store on your device. This data is read live each time you open the app and is not uploaded to or stored on our servers. When you finish a workout, Rust may write an estimated active-calorie total for that session back into Apple Health / Health Connect so it's reflected in your device's native Activity totals — that's the only data Rust writes. Access is opt-in: nothing is requested until you tap "Connect" and approve the native permission screen, and you can revoke access at any time in Health Connect settings or iOS Settings → Privacy & Security → Health. See the dedicated Health Data Privacy page for more detail.

Health-Related Information

Some information you may choose to share with the AI coach — such as an injury, pain, soreness, or sleep and energy levels — is health-related. We treat this with extra care: it is used only to give you more relevant coaching advice, is never sold, and is never shared for advertising or marketing purposes. If you're not comfortable sharing this kind of detail with the AI coach, you can simply choose not to — the app's core workout tracking works fully without it.

Your Choices

Access & correction — you can view and edit most of your data directly in the app (Settings, Profile, and workout history screens).
Clear coach chat history — use the "Clear" button inside the AI coach at any time to delete your stored conversation with it.
Deletion — to delete your account and associated data (including workout data and everything the AI coach has stored or remembered about you), contact us at the email below. We'll confirm and complete deletion within a reasonable time, except where we're required to retain limited records by law.
Export — you can request a copy of your data by contacting us.

Children's Privacy

Rust is not directed at children under 13, and we do not knowingly collect information from children under 13. If you believe a child has provided us information, contact us and we'll remove it.

Changes to This Policy

We may update this policy as the app changes. We'll update the date at the top of this page when we do. Material changes affecting how your data is used will be communicated in the app.

Contact Us

Questions about this policy or your data? Reach us at: heath.shepard@kw.com