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Doku — Sudoku Reinvented

Privacy Policy

Doku — Sudoku Reinvented

Introduction

Happy App Studio develops Doku, a daily puzzle game inspired by sudoku. We take the protection of your privacy very seriously. This privacy policy explains what data is collected when you use the app and how it is processed.

Account and sign-in

Doku lets you create an account by signing in with Google or Apple. During sign-in, we receive a unique identifier and, depending on the service and your settings, your name and email address. This information is used to create and secure your account. With « Sign in with Apple », you can choose to hide your email address.

Profile and friends

To use the social features, you choose a username that is visible to other players. You can add friends, for example via an invitation link, in order to compare your results. Your username and friends list are stored to make these features work.

Game data

We store your progress, scores and statistics so we can sync your game across your devices and build the leaderboards.

Data hosting

Your account data is stored securely on the Firebase / Google Cloud infrastructure.

Advertising

Doku may display ads, in particular through Google AdMob. Where applicable, AdMob may collect certain identifiers from your device and usage information in order to serve ads. To learn more, see Google's privacy policy: https://policies.google.com/privacy

In-app purchases and Doku+

Doku may offer a Doku+ subscription giving access to additional features and the removal of ads. Where applicable, payments are processed by Apple or Google, and subscription management may rely on RevenueCat. No payment information is collected or stored directly by Happy App Studio. For more information, see RevenueCat's privacy policy: https://www.revenuecat.com/privacy

Analytics

Doku uses Firebase Analytics to collect anonymous usage data, such as how often the app is used and which features are accessed. This data helps us improve the user experience.

Data retention and deletion

You can delete your account at any time from within the app or by contacting us. Your associated personal data is then deleted, unless we are legally required to retain it.

Your rights

In accordance with the GDPR, you have the right to access, rectify and delete your data. To exercise these rights, contact us at hello@happyapp.studio.

Minimum age

You must be at least 13 years old to use Doku, or have the permission of a parent or legal guardian.

Contact

For any questions about this privacy policy, you can contact us at the following address: hello@happyapp.studio

Last updated : 2026-06-13