OtoTheory

Privacy Policy

Last updated: February 21, 2026

Controller: TH Quest (Kamakura, Kanagawa, Japan) · support@ototheory.com

1. Data We Collect

OtoTheory collects only the minimum data needed to provide and improve the service: device identifiers, in-app purchase status, usage events (e.g., chord progression playback, export), diagnostics (crash/performance), and approximate location derived from IP address. We do not access your contacts, photos, or files. If you contact our support team via email, your email address is used solely for support purposes.

Advertising (iOS Free plan only): The free version displays ads via Google AdMob. Device identifiers (IDFA/IDFV) may be collected for ad delivery. Consent is managed via Google UMP, and you can withdraw consent anytime in Settings.

2. Where Your Data Is Stored

OtoTheory does not store your personal data on its own servers. Your data is stored in the following locations:

Data TypeStorage LocationManaged By
iOS Sketch dataYour device (local)You
iOS Cloud sync data (Pro)Your iCloud account (Apple CloudKit)You / Apple
Web Sketch dataYour browser (localStorage)You
iOS AnalyticsFirebase Analytics (Google)Google
Web AnalyticsGoogle Analytics 4 (Google)Google
iOS Ad data (Free only)Google AdMobGoogle
Both Hosting logsVercel (website hosting)Vercel

3. Purposes

We use collected data to provide app features (sketch saving, MIDI/audio export, etc.), improve the product through analytics, handle customer support, and send important service notices. For the iOS Free plan, Google AdMob displays ads to sustain free access.

4. Third-Party Services

We never sell your personal data. OtoTheory uses the following third-party services, and their handling of your data is governed by their respective privacy policies:

Firebase AnalyticsiOS app analytics
Firebase privacy policy →
Google Analytics 4Web analytics
Google privacy policy →
Google AdMobiOS Free plan ads
Google privacy policy →
Apple CloudKitPro cloud sync
Apple privacy policy →

5. Data Retention and Deletion

Device data: Sketch data is stored on your device. Uninstalling the app removes it completely.

iCloud data: If you use Pro cloud sync, sketch data is stored in your iCloud account. You can manage or delete it via iOS Settings → Apple ID → iCloud → Manage Storage → OtoTheory.

Third-party data: Data held by Firebase Analytics, Google Analytics 4, AdMob, and similar services is subject to their respective privacy and retention policies.

For deletion requests or questions, contact us at support@ototheory.com. We will respond within the scope we can support.

6. Security

All communications are encrypted via HTTPS. Website hosting uses Vercel (global CDN). iOS cloud sync uses Apple CloudKit's encrypted infrastructure.

7. Your Rights

Device data is completely erased by deleting the app. iCloud data can be deleted from iOS Settings → Apple ID → iCloud → Manage Storage → OtoTheory. For questions about other data, contact support@ototheory.com.

8. Children

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

9. Changes to This Policy

We will notify you of significant changes on this page. Continued use of OtoTheory after changes constitutes acceptance of the updated policy.

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