Privacy Policy
Short version: Eigencards works without an account and keeps your study data on your device. What it sends to our servers is anonymous card-performance and feedback signals — never sold, never used to track you across other apps. The one exception is optional: if you sign in to Game Center, your learning record (answer history and EigenScore) is saved to your Game Center identity so it syncs across your devices — tied to you, but used only to restore your progress and keep competition fair.
No sign-up. Your progress, ratings, and settings live on your device. We collect anonymous, non-identifying telemetry about how cards perform (so we can fix bad cards and calibrate difficulty). Purchases go through Apple — we never see your card details. Ads aren't live yet; when they are, any personalized advertising will require your explicit permission (Apple's App Tracking Transparency prompt) and you can decline and still use the app.
What we collect
| Data | Why | Identifies you? |
|---|---|---|
| Card attempts (correct/incorrect, time taken), card & concept reports, edit proposals | Calibrate difficulty and detect/repair low-quality cards | No — sent anonymously, keyed only by card ID |
| Your progress, EigenScore, streaks, settings | Run the app; spaced-repetition scheduling | Stored on your device; uploaded to your Game Center identity only if you sign in (to sync & restore across devices) |
| Subscription status | Unlock Pro features | Provided by Apple; we don't receive payment details |
| Learning record — answer history & EigenScore (optional, Game Center) | Sync/restore your progress across devices; keep EigenArena competition fair (tamper-evident, server-verifiable) | Yes — tied to your Game Center identity; app functionality only, never advertising or cross-app tracking |
| Game Center identity (optional) | EigenArena leaderboards / friends and the synced learning record above, only if you opt in | Managed by Apple; you choose your nickname |
How we use it
Only to run and improve Eigencards: schedule your reviews, compute your EigenScore, and keep the card pack accurate. Anonymous, aggregated performance data feeds our public quality report and the nightly review that repairs flagged cards.
What we don't do
- We don't sell or rent your data.
- We don't require an email or account to use the free tier.
- We don't track you across other companies' apps or websites — and if that ever changes (advertising), it will only happen with your explicit consent.
Third parties
- Apple — StoreKit (purchases) and, optionally, Game Center. Governed by Apple's privacy policy.
- Microsoft Azure — hosts the anonymous feedback service that receives card-performance signals.
- Google AdMob (planned, not yet live) — when free-tier rewarded ads ship, AdMob may use the device advertising identifier (IDFA) only if you allow tracking via Apple's prompt; otherwise you'll see non-personalized ads. We'll update this policy and our app privacy details before any ad ships.
Your choices
- Tracking: decline the App Tracking Transparency prompt (or change it in iOS Settings ▸ Privacy & Security ▸ Tracking) — the app still works.
- Local data: deleting the app removes your on-device study data.
- Game Center: entirely optional; sign out anytime.
Children
Eigencards is intended for a general audience studying data science and ML, not directed at children under 13. We don't knowingly collect personal information from children.
Data retention
On-device data persists until you delete the app. Anonymous telemetry is retained in aggregate for quality monitoring and calibration; because it isn't tied to your identity, it can't be linked back to you.
Changes
We'll post any changes here and update the date above. Material changes (like introducing advertising) will be called out before they take effect.
Contact
Questions about privacy? Email distayne@shutoffswitch.com.