Privacy Policy

Last updated: October 14, 2026

1. Who is responsible

The controller within the meaning of the General Data Protection Regulation (GDPR) is:

This policy applies to the DilDuel app for Android and iOS and to this website. We have not appointed a data protection officer.

2. The short version

• Without an account (guest mode), your bookmarks, progress and results are stored only on your device. We do not receive them.
• If you create an account, we store your account details and your learning data in the cloud so that they can be synced between your devices.
• We do not use analytics or tracking tools of our own. The app shows advertising from Google AdMob, and only after your consent where the law requires it (see “Advertising”).
• You can delete your account and all cloud data at any time.

3. Using the app without an account

The app stores the following data locally on your device: bookmarked words, words marked as unknown, training progress, quiz and listening results, recent searches, and your language and theme settings. This data is not transmitted to us.

Storing it is technically necessary to provide the functions you request (Section 25(2) no. 2 TDDDG; Art. 6(1)(b) GDPR). You can remove it at any time by clearing the app's storage or uninstalling the app.

4. Account and sign-in

If you create an account or sign in, we use Firebase Authentication, a service of Google. Depending on the method you choose, the following data is processed:

• Email and password: your email address, your display name and your password. The password is handled only by Firebase Authentication; we never see it in plain text.
• Sign in with Google: the name, email address and profile picture link that Google shares with the app.
• Sign in with Apple: the name and email address Apple shares with the app. If you use “Hide My Email”, we only receive Apple's relay address.

We also store a user ID that Firebase assigns to your account. Purpose: creating and managing your account and recognising you when you sign in. Legal basis: Art. 6(1)(b) GDPR (performance of the contract for the use of the app).

5. Cloud synchronisation

While you are signed in, the following data is stored in the cloud database Cloud Firestore (Google) so that you can use it on several devices: your email address, bookmarked words, words marked as unknown, training progress per level and topic, and quiz and listening results. Legal basis: Art. 6(1)(b) GDPR.

If you already have data on your device when you sign in, the app asks whether you want to keep it (it is then merged into your account) or discard it.

6. Technical data

When the app communicates with Firebase (sign-in and sync), Google processes technical data such as your IP address, device and connection information and timestamps to deliver the service and to ensure security. We have no influence on this processing. Legal basis: Art. 6(1)(f) GDPR (legitimate interest in a secure and functioning service).

7. Fonts

The app displays text in the typefaces Plus Jakarta Sans and Source Serif 4, which it loads from Google Fonts. When it does, your IP address is transmitted to Google servers. Legal basis: Art. 6(1)(f) GDPR (a consistent appearance of the app).

8. Speech output

The app can read German words aloud. For this it uses the speech synthesis (text-to-speech) built into your device's operating system. Depending on the voice and settings you have installed, your device's speech service may process the spoken word online. We do not receive this data and have no influence on it.

9. This website

This website is hosted on GitHub Pages (GitHub, Inc., USA). When you visit it, GitHub processes technical data such as your IP address in server logs. Legal basis: Art. 6(1)(f) GDPR (legitimate interest in presenting our app securely). The information pages use no cookies, analytics, or external fonts or scripts. The account deletion page loads Google's Firebase scripts and connects to Firebase so that you can sign in and delete your data; Google then processes technical data such as your IP address (Art. 6(1)(b) and (f) GDPR).

10. Advertising (Google AdMob)

The app shows banner advertising from Google AdMob (Google Ireland Limited; Google LLC, USA). The banner appears at the bottom of some screens, such as the dictionary search and the training, test and bookmark screens.

Before any ad is loaded, we ask for your consent where the law requires it, using Google's consent form (User Messaging Platform). On iOS we also ask, through Apple's tracking prompt, whether the app may track you across apps and websites of other companies. If you do not consent, advertising is limited accordingly: depending on your choice you will see non-personalised ads or no ads.

When an ad is requested, Google and its advertising partners process data such as your IP address, device and advertising identifiers, information about the app and your interaction with ads, and the approximate location derived from your IP address, in order to deliver, measure and personalise ads and to prevent fraud. We do not receive this data and have no influence on this processing. Legal basis: your consent (Art. 6(1)(a) GDPR; Section 25(1) TDDDG). More information: Google's privacy policy.

You can change or withdraw your choice at any time under Settings → Privacy options for ads (shown where consent applies). On iOS you can also change the tracking permission in the system settings. Withdrawal does not affect the lawfulness of processing carried out until then.

11. No analytics or tracking by us

The app does not use analytics or crash-reporting tools, and it does not access your location, contacts, camera or microphone. The only third-party tracking technology is the advertising described above, which depends on your consent. There is no automated decision-making or profiling by us within the meaning of Art. 22 GDPR.

12. Recipients and transfers to third countries

We use these service providers, who process data on our behalf: Google Ireland Limited, Gordon House, Barrow Street, Dublin 4, Ireland (Firebase Authentication, Cloud Firestore and Google Sign-In); Apple Distribution International Ltd., Cork, Ireland (Sign in with Apple, if you use it); Google Ireland Limited and Google LLC, USA (Google AdMob advertising, with your consent); GitHub, Inc., USA (website hosting).

Data may be processed in countries outside the EU, in particular the USA. Where this happens, the transfer relies on the EU–US Data Privacy Framework adequacy decision or on standard contractual clauses.

13. Storage period and deletion

Data on your device stays there until you delete it. Account and cloud data are kept until you delete your account. You can do this in the app under Settings → Delete account, on our account deletion page, or by emailing us. Deletion removes your account and all cloud data immediately; routine backups at Google are overwritten on Google's regular schedule.

14. Your rights

You have the right to:

• access your data (Art. 15 GDPR),
• have inaccurate data corrected (Art. 16 GDPR),
• have your data erased (Art. 17 GDPR),
• restrict processing (Art. 18 GDPR),
• receive your data in a portable format (Art. 20 GDPR),
• object to processing based on legitimate interests (Art. 21 GDPR),
• withdraw consent you have given, with effect for the future (Art. 7(3) GDPR).

To exercise your rights, contact us at elvin.m@hotmail.com. You also have the right to lodge a complaint with a data protection authority. The authority responsible for us is: Der Hamburgische Beauftragte für Datenschutz und Informationsfreiheit, Ludwig-Erhard-Str. 22, 20459 Hamburg, Germany, datenschutz-hamburg.de.

15. Required data and children

You do not have to provide personal data to use the app; an account is optional. The app is not directed at children under 16, and we do not knowingly collect their personal data.

16. Security

Data between the app and our service providers is transmitted encrypted (TLS).

17. Changes

We may update this policy when the app or legal requirements change. The current version is always available on this page.