Privacy Policy

Last updated: April 30, 2026

Cinder ("we," "our," or "the app") is an AI-powered run coaching app built by Dustin Nielsen. We take your privacy seriously. This policy explains what data we collect, how we use it, and your rights.

1. Data stored on your device

Cinder stores the following data locally on your device only using Apple's secure on-device storage. This data never leaves your device except as described in Section 2.

• Location data — GPS coordinates recorded during runs to track your route, distance, and pace. Stored as part of your workout history.
• Workout data — Run logs including duration, distance, pace, and route GPS points.
• Health & wellness check-ins — Sleep quality, energy level, and stress ratings you enter each morning.
• Training plan — Your generated training schedule, goal race, and ability level.
• Shoe mileage — Shoe names and accumulated mileage you track manually.
• Personal records and milestones — Achievements earned within the app.

This data is stored in AsyncStorage on your device. It is not synced to any cloud service operated by us.

2. Data sent to third-party services

Anthropic (AI coach chat)

When you use the AI coach chat, your messages and relevant context (recent workout data, training plan summary) are sent to Anthropic, PBC to generate responses. Anthropic processes this data according to their Privacy Policy. We do not store chat messages after your session ends.

Strava (optional integration)

If you connect your Strava account, your completed run data is sent to Strava, Inc. according to their Privacy Policy. This connection is optional and can be disconnected at any time from within the app.

3. Location data

Cinder requests access to your precise location while a run is active, including when the app is in the background or your screen is off. Location data is used solely to record your run route and calculate distance and pace. We do not use location data for advertising or share it with any parties other than Strava if you have enabled that integration.

You can revoke location access at any time in Settings → Privacy & Security → Location Services → Cinder.

4. Data we do not collect

• We do not create user accounts or collect your name or email address.
• We do not use analytics SDKs or advertising networks.
• We do not sell your data to any third party.
• We do not share your data with any party except Anthropic (AI chat) and Strava (if you opt in).

5. Children's privacy

Cinder is not directed to children under 13. We do not knowingly collect personal information from children under 13.

6. Data deletion

All data is stored locally on your device. To delete your data, delete the Cinder app from your iPhone. If you have connected Strava, you may also disconnect and revoke access from Strava's connected apps settings.

7. Changes to this policy

If we make material changes to this policy, we will update the "Last updated" date above. Continued use of the app after changes constitutes acceptance of the updated policy.

8. Contact

Questions? Email us at dustin@dnilly.com