Privacy Policy
Applies to the Waddlu app and this website. Last updated: 28 October 2026
In short: Waddlu doesn’t need an account, and your learning progress is stored only on your device. The app is free and is financed by ads from an advertising partner. Section 4 explains what that means for your data and the choices you have. Lesson ratings you choose to send are anonymous.
1. Who is responsible
The controller responsible for processing personal data under the Swiss Federal Act on Data Protection (FADP) and, where it applies, the EU General Data Protection Regulation (GDPR) is:
Elias Piersig
Limmattalstrasse 244
8049 Zürich
Switzerland
Email: hello@waddlu.com
2. Data in the app
Waddlu works without an account or sign-in. The app stores the following information only locally on your device:
- your learning progress (completed lessons and sections),
- your experience points (XP), your title and your streak,
- how many final quiz attempts you have used today,
- the display name you choose and your profile picture (a character from the app, not a photo),
- your settings, such as language, sound and reminder times.
This data is never transferred to us or to third parties. There is no cloud sync and we have no access to it. You can reset your progress at any time in the app under Profile › Delete progress. Deleting the app removes all locally stored data.
Apart from advertising (section 4) and the optional lesson feedback (section 3), the app does not use any analytics or tracking services. All lesson content is built into the app, so it also works without an internet connection.
3. Anonymous lesson feedback
After finishing a lesson, you can choose to leave a rating. Only when you tap Send does the app send the following to our server:
| Data | Purpose |
|---|---|
| Lesson number | Linking the rating to a lesson |
| Star rating (1 to 5) and your optional comment | Improving our content |
| Number of mistakes in that lesson, whether it was a final quiz and whether it was passed | Telling apart lessons that are too hard from ones that are unclear |
| App language, app version, operating system (iOS or Android), time | Troubleshooting and context |
No device ID, name, profile picture or any other identifier is sent, and we do not store IP addresses. A rating therefore cannot be linked to you. Please don’t include personal details in your comment.
Ratings are sent over an encrypted connection (HTTPS) to a service we run on Cloudflare, Inc., 101 Townsend St., San Francisco, CA 94107, USA (Cloudflare Workers and D1 database). For technical reasons, Cloudflare briefly processes your IP address while establishing the connection, in order to deliver the request and protect against abuse. Cloudflare is certified under the EU-US and Swiss-US Data Privacy Frameworks, and our data processing agreement with Cloudflare includes the EU Standard Contractual Clauses.
The legal basis is your choice to submit (Art. 6(1)(a) GDPR) and our legitimate interest in improving our lessons (Art. 6(1)(f) GDPR). Ratings are deleted once they are no longer needed to improve the content, and at the latest after 24 months.
If a rating can’t be sent because you’re offline, the app keeps it on your device and tries again later. At most 20 ratings are held this way.
4. Advertising
Waddlu is free to use and is financed by ads shown in the app. For ads we use Unity LevelPlay, a platform that serves ads from several ad networks. It is provided by Unity Technologies SF, 116 New Montgomery Street, Suite 200, San Francisco, CA 94105, USA (EU contact: Unity Technologies ApS, Niels Hemmingsens Gade 24, 1153 Copenhagen, Denmark). Through LevelPlay, ads may come from these ad networks:
- Unity (ironSource Ads and Unity Ads): privacy policy
- Google AdMob (Google Ireland Limited, Gordon House, Barrow Street, Dublin 4, Ireland): privacy policy
These providers may process the following to show and measure ads and to protect them against fraud:
- your device’s advertising identifier (IDFA on iOS, Advertising ID on Android), where you allow it,
- your IP address and an approximate location derived from it,
- device and app information, such as device model, operating system, language and app version,
- interactions with ads, such as which ads were shown or tapped.
When you are asked. Your first lessons are ad-free. The app asks for your consent only shortly before an ad could be shown to you for the first time. Until then the ad technology is not started, and with Waddlu Pro it is never started.
Your consent. In the EU, EEA and UK, we ask through Google’s User Messaging Platform (Google Ireland Limited, Gordon House, Barrow Street, Dublin 4, Ireland). It shows a consent form certified under the IAB Transparency & Consent Framework, stores your choice on your device and passes it on to the ad networks. The app checks with Google on every launch whether the form is needed for you. For this, Google processes your IP address and technical information about your device and the app. In all other countries, including Switzerland, the app asks its own question. If you decline, you only see non-personalised ads, which rely on limited data such as the app and your approximate location. You can change or withdraw your choice at any time under Profile › Ads. On iOS, the app also asks for permission to track via Apple’s App Tracking Transparency. You can change this under Settings › Privacy & Security › Tracking. On Android, you can reset or delete your Advertising ID in your device settings.
For users in the EU and EEA, the legal basis for personalised ads and for accessing information on your device is your consent (Art. 6(1)(a) GDPR and the applicable national ePrivacy rules). The legal basis for non-personalised ads is our legitimate interest in financing the app through advertising (Art. 6(1)(f) GDPR). The legal basis for asking for consent through Google is our legal obligation to obtain your consent and be able to prove it (Art. 6(1)(c) GDPR). Google is certified under the EU-US and Swiss-US Data Privacy Frameworks. Unity and the ad networks may transfer data to countries outside Switzerland and the EU, in particular the USA. Such transfers only take place with appropriate safeguards: the Data Privacy Frameworks where the recipient is certified, and otherwise the EU Standard Contractual Clauses.
Ads come from third parties. They are not recommendations from us, and Waddlu is not responsible for the advertised products or services.
5. Waddlu Pro and purchases
Waddlu Pro unlocks unlimited final quiz attempts and removes ads. Purchases are handled entirely by the App Store (Apple) or Google Play. Payment details never reach us. The app only stores locally whether Waddlu Pro is active, and asks the store which purchases belong to your store account.
6. Reminders
If you turn on study reminders, the app asks your operating system for permission to show notifications. Reminders are scheduled entirely on your device. No push service is used and no data is sent to us. You can turn reminders off at any time in the app or in your device settings.
7. This website
Hosting
This website is served via Cloudflare Pages by Cloudflare, Inc. (address above). When you visit, Cloudflare processes technically necessary data, in particular your IP address, the date and time of access, the page requested, the referring URL, and browser and operating system information. This is needed to deliver the website, keep it secure and defend against attacks.
The legal basis is our legitimate interest in providing the website securely and reliably (Art. 6(1)(f) GDPR). Transfers to the USA are based on the EU-US and Swiss-US Data Privacy Frameworks and supplementary Standard Contractual Clauses. For more information, see Cloudflare’s privacy policy.
No cookies, no tracking
This website sets no cookies, uses no analytics or tracking services and embeds no third-party content. Even the fonts are loaded directly from our own server rather than from an external provider. That’s why there is no cookie banner here.
8. Contacting us by email
If you email us, we process your email address and the content of your message in order to respond (Art. 6(1)(b) or (f) GDPR). We delete this data once your request has been dealt with, unless we are legally required to keep it.
9. App stores
Waddlu is distributed through Apple’s App Store and Google Play. When you download the app, these platforms process data such as your account details, device information and purchase history under their own responsibility. We have no influence over this. Their respective privacy policies apply: Apple and Google.
10. Your rights
Where we process personal data about you, you have rights under the FADP and, where it applies, the GDPR, in particular the right to:
- access the data we hold (Art. 15 GDPR),
- have inaccurate data corrected (Art. 16 GDPR),
- have data deleted (Art. 17 GDPR) or its processing restricted (Art. 18 GDPR),
- data portability (Art. 20 GDPR),
- object to processing based on legitimate interests (Art. 21 GDPR),
- withdraw any consent you have given, with effect for the future (Art. 7(3) GDPR).
Because feedback is stored anonymously, we usually can’t link a single rating to you. If you tell us roughly when you sent it and what your comment said, we’ll gladly delete it. To exercise your rights, email hello@waddlu.com.
You also have the right to lodge a complaint with a data protection supervisory authority. In Switzerland, this is the Federal Data Protection and Information Commissioner (FDPIC), Feldeggweg 1, 3003 Bern. If you live in the EU or EEA, you can also contact the supervisory authority in your country.
11. Changes
We will update this privacy policy whenever the app or this website changes, for example when new features are added. The current version is always available on this page.