Privacy Policy
Last updated: October 17, 2026
Derivon ("the App") respects your privacy and is committed to protecting your personal information. This policy explains what information the App collects and how it is used.
1. Information We Collect
The App collects and stores the following information:
- Account information: User ID and email address (optional) obtained when signing in with Apple ID or Google account
- Profile information: Display name (nickname) and avatar set by the user
- Game progress data: Star Sand earned/spent, planet exploration and completion status, daily streak, experience points (XP), and Shooting game scores
- Learning history: Questions answered, results (correct/incorrect), and timestamps (up to 100 records)
- Friend information: Follow relationships (IDs of connected users) when you use the Friends feature
- Usage data: Screens viewed and buttons tapped in the App, device model and OS version, approximate region (estimated from your IP address), and an identifier generated by the App. This is not linked to your sign-in user ID or email address.
- Problem reports and feedback: What you send with the report button or the feedback form (the reason, your note, or your feedback text), the content of the reported question (question, choices, answer, and explanation), the App version, display language, and OS version. If you are signed in, your user ID is stored with it. We use this only to fix questions and improve the App, and delete it after about one year.
- Advertising ID: Your device's advertising identifier (IDFA), only if you allow tracking
2. How We Use Your Information
- Syncing game progress across multiple devices
- Providing and improving in-app features
- Maintaining stable service operations
- Analyzing how the App is used (for example, where people stop using it) to improve it
- Showing ads in the App
3. Third-Party Services
The App uses the following third-party services. Please review their respective privacy policies:
- Firebase (Google LLC): Used for authentication and cloud data storage.
Firebase Privacy Policy - Google Analytics for Firebase (Google LLC): Aggregates the usage data above to improve the App. It is not used to personalize ads.
How Google uses data from apps that use its services - Google AdMob (Google LLC): Used to show ads in the App. AdMob collects device information and approximate location to deliver and measure ads. If you allow tracking, your advertising ID is used to show ads tailored to you; if you do not, the advertising ID is not used. You can change this at any time in Settings > Privacy & Security > Tracking.
Google Advertising Policy - Sign in with Apple (Apple Inc.): Used for account authentication.
- Google Sign-In (Google LLC): Used for account authentication.
Google Privacy Policy - StoreKit / App Store (Apple Inc.): Used for in-app purchase processing. Purchase information (transaction ID, purchase date, product ID) is managed by Apple. The developer only verifies receipts provided by Apple. Payment details such as card information are never shared with the developer.
Apple Privacy Policy
4. Information Sharing
The App does not share collected information with third parties, except in the following cases:
- When disclosure is required by law
- With the user's consent
5. Friends Feature and Visibility to Other Users
The App includes a Friends feature. If you use it, the following information becomes visible to other users you connect with (follow / friends):
- Your display name (nickname), chosen avatar, level, daily streak, best streak, collection completion rate, and whether you have studied today
Your nickname does not have to be your real name and can be changed at any time. You can add or remove friends, block abusive users, and report inappropriate users or content. Reports (reporter, reported user, and reason) are sent to us for safety review. Friend-related public information is no longer visible to other users once you delete your account.
6. Data Storage and Deletion
Collected data is stored on Firebase (Google LLC servers). To delete your account and associated data, please contact us through the support page. Data will be deleted within 30 days of the request.
7. "Request a Unit" Form on the Website
When you use the "Request a unit" form on the printable worksheets page of derivon.app, we store what you send (the unit, an optional comment, the page you sent it from, and the date and time) in Google Cloud (Google LLC servers). We use it only to decide which worksheets to add, and we do not share it with third parties. We do not ask for your name or contact details. Each request is deleted automatically about one year after it was sent. To prevent abuse, we keep a one-way transformed value of your IP address and a count of how many times it was used to send the form, for up to about 16 days after the last time it was used (we do not store the IP address itself). Vercel (Vercel Inc.), which serves this website, also handles IP addresses as part of its connection logs. To have something you sent deleted, please contact us through the contact form and tell us the unit, the comment, and roughly when you sent it.
8. Children's Privacy
The App is not intended for children under 13. We do not knowingly collect information from children under 13.
9. Changes to This Policy
This privacy policy may be updated as needed. Users will be notified of significant changes within the App.
10. Contact Us
If you have questions about this policy, please reach out via our contact form.