Privacy Policy — MostUsedWords App
Last updated: August 14, 2026
This Privacy Policy applies to the MostUsedWords application ("the App"),
available on iOS, Android, and the web at app.mostusedwords.com. It does
not apply to the MostUsedWords webshop (mostusedwords.com) 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), Google (Play Store), or, for
purchases made on our website (mostusedwords.com) or the web app
(app.mostusedwords.com), Paddle Payments Ltd ("Paddle"), acting as
Merchant of Record. 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 via Firebase Analytics (Google), including
study sessions completed, which language is active, sign-up and login
events, and checkout funnel events (which plan you view or select, and
the amount and currency of a completed purchase). This data is used to
understand how the App is used and to improve it. On the web app, some
of this data (excluding purchase amounts) may also be used, with your
consent, to measure the effectiveness of our advertising. Legal basis:
legitimate interest (improving the app) for the mobile app; consent for
the additional advertising-related use on the web app described below.
Advertising and cookies (web app only)
The web app (app.mostusedwords.com) uses a Google Ads remarketing tag
to build advertising audiences — for example, to show ads to people who
have visited the App but not completed a purchase. This uses cookies
and similar technologies to recognize your browser. It does not use
your name or email address.
This only activates if you have given cookie consent via the consent
banner shown on mostusedwords.com; your choice there is carried over to
the web app. If you decline or have not yet made a choice, only
strictly necessary functionality runs and no advertising or analytics
cookies are set. You can change your choice at any time by clearing
your cookies and revisiting mostusedwords.com, or by using your
browser's privacy settings to block third-party cookies.
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
- Paddle Payments Ltd ("Paddle") — payment processing and Merchant
of Record for purchases made on our website and web app.
Privacy policy: paddle.com/legal/privacy
- Firebase Crashlytics and Firebase Analytics (Google LLC) — crash
reporting and anonymized usage analytics.
Privacy policy: firebase.google.com/support/privacy
- Google Ads (Google LLC) — advertising remarketing on the web app,
active only with cookie consent.
Privacy policy: policies.google.com/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. Advertising cookies set on the web app expire
according to Google's standard retention periods (see Google's
privacy 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
- Withdraw consent (for advertising cookies, via the cookie banner or
your browser settings)
- 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