Privacy Policy
Datenschutzerklärung gemäß DSGVO / GDPR
1. Responsible party (Controller)
The controller responsible for the processing of personal data on this website is the operator named in the Impressum, where you will find the operator's name, postal address, and contact details. (Impressum)
2. Data we collect
We collect the following data when you use this service:
- Email address (via Google account login)
- First name and full name (via Google account, used to display who is logged in)
- Children's learning data: quiz answers, kanji mastery levels, date of birth (for grade calculation)
- Usage data: pages visited, session duration (via Google Analytics)
3. Purpose and legal basis
- Account authentication and identification — Art. 6(1)(b) GDPR (contract performance)
- Providing the learning service and tracking progress — Art. 6(1)(b) GDPR
- Service analytics and improvement — Art. 6(1)(f) GDPR (legitimate interest)
4. Sub-processors (third-party services)
- Amazon Web Services (AWS) — cloud infrastructure, database, AI inference
- Stripe — payment processing
- Google Analytics (GA4) — usage analytics
- Amazon Cognito / Google Sign-In — authentication
5. International data transfers
Our infrastructure, database, and AI inference run on Amazon Web Services in a United States region (North Virginia), and Stripe and Google likewise process data in the United States. Your personal data is therefore transferred to and processed in the United States, which is a third country under the GDPR.
These transfers are protected by appropriate safeguards pursuant to Chapter V of the GDPR — in particular the EU-U.S. Data Privacy Framework, under which these providers are certified, and/or the European Commission's Standard Contractual Clauses (Art. 46 GDPR). Copies of these safeguards are published by the respective providers and are available on their websites.
6. Children's data
Kanjidou is designed to be used by a parent or legal guardian on behalf of their child. Children do not create their own account and do not sign in themselves; the account holder manages all learner profiles and their data.
- When adding a learner, the account holder must confirm that they are the parent or legal guardian and give explicit consent to the collection and processing of that learner's learning data. For learners under 16, this parental consent is required, and the date and time it was given are recorded (legal basis: Art. 6(1)(a) and Art. 8 GDPR).
- We process only the learning data needed to provide and personalise the service: quiz answers, kanji mastery levels, and the learner's date of birth (used solely to determine the appropriate grade level). We do not request or store a child's email address, phone number, or other direct contact details.
- The account holder can review, correct, or delete a learner's data at any time from within the app, and can delete the entire account — which erases all associated learner data — at any time.
7. Data retention
We retain personal data only for as long as your account exists and the data is needed to provide the service.
- When you delete your account or an individual learner, the associated personal data — including all learning data, uploaded materials, and account information — is erased from our live systems immediately. Any residual copies contained in automated database backups are removed automatically as those backups age out of their short retention window.
- Some records are kept longer where the law requires it: payment and invoice records are retained by our payment processor (Stripe) for accounting and tax purposes, while the customer object holding your contact and payment details is deleted.
- We keep a minimal deletion-confirmation record as proof that an erasure request was fulfilled. It contains no personal data — only a reference number, timestamps, and per-category deletion counts.
8. Your rights
Under GDPR you have the right to access, rectify, erase, restrict processing of, and port your data, and to object to processing. To exercise these rights, contact us via the address in the Impressum.
9. Contact
For privacy-related enquiries, please use the contact details in the Impressum.
Last updated: 2026-07-24. The German-language version is the legally binding reference.