Privacy Policy — MostUsedWords App
Last updated: July 5, 2026
This Privacy Policy applies to the MostUsedWords mobile application
("the App"), available on iOS and Android. It does not apply to the
MostUsedWords webshop or any other products on this website.
1. Who we are
MostUsedWords App is operated by MUW EDU (contact: info@muw-edu.com).
We are the data controller for the personal data described below.
2. What data we collect and why
Account data
When you create an account, we collect your email address. We use this
to authenticate you, send password reset emails, and link your study
progress to your account. Legal basis: contract performance.
Study progress
Your flashcard history — which cards you've studied, your ratings
(Again / Hard / Good / Easy), scheduled review dates, and streak data
— is stored on your device and synced to our servers so you can
continue studying across devices and after reinstalling the app.
Legal basis: contract performance.
Purchase history
When you purchase a subscription or lifetime access, the transaction
is processed by Apple (App Store) or Google (Play Store). We receive
confirmation that a subscription is active and its type (monthly,
yearly, or lifetime). We do not receive your full payment details.
This data is used solely to unlock app features. Legal basis: contract
performance.
Crash and diagnostic data
If the app crashes or encounters an error, anonymized crash reports
and stack traces are sent to Firebase Crashlytics (Google). These
reports do not contain your email or study content — only technical
information about what went wrong. Legal basis: legitimate interest
(maintaining a stable app).
Usage analytics
We collect anonymized events such as study sessions completed and
which language is active, via Firebase Analytics (Google). This data
is aggregated and does not identify you personally. Legal basis:
legitimate interest (improving the app).
3. Third-party services
The following services process data on our behalf:
- Supabase (Supabase Inc.) — account authentication and cloud data
storage. Privacy policy: supabase.com/privacy
- PowerSync (Journey Mobile Inc.) — real-time sync between your
device and our servers. Privacy policy: powersync.com/legal/privacy
- RevenueCat Inc. — subscription and purchase management.
Privacy policy: revenuecat.com/privacy
- Firebase Crashlytics and Firebase Analytics (Google LLC) — crash
reporting and anonymized usage analytics.
Privacy policy: firebase.google.com/support/privacy
We do not sell your data to any third party.
4. Data retention
Account and study data is retained for as long as your account is
active. You can request deletion at any time by using the
"Delete account" option in the app's Settings screen. This
permanently deletes your account and all associated study progress.
Crash reports are retained by Google for 90 days per Firebase's
default policy.
5. Your rights (GDPR)
If you are based in the European Economic Area, you have the right to:
- Access the personal data we hold about you
- Correct inaccurate data
- Delete your data (use "Delete account" in Settings, or email us)
- Restrict or object to processing
- Data portability
To exercise any of these rights, email info@muw-edu.com.
6. Children
The App is not directed at children under 13. We do not knowingly
collect data from children under 13. If you believe a child has
provided us with personal data, contact us and we will delete it.
7. Changes
We may update this policy. The "Last updated" date at the top will
reflect any changes. Continued use of the App after an update
constitutes acceptance of the revised policy.
8. Contact
MUW EDU — info@muw-edu.com