Privacy Policy — Einbürgerungstest & DTZ

Last updated: 2026-07-10

This Privacy Policy (Datenschutzerklärung) describes how the app Einbürgerungstest & DTZ ("we", "us", "the app") collects, uses, and protects your information when you use our mobile and web applications. We process personal data in accordance with the EU General Data Protection Regulation (GDPR / Datenschutz-Grundverordnung, DSGVO).

Provider / Operator (Anbieter): Kelly Zwart, Amsterdam, Netherlands — contact: kell@chefzwart.nl

The app helps you prepare for the German naturalisation test Einbürgerungstest ("Leben in Deutschland") and the DTZ (Deutsch-Test für Zuwanderer). We are an independent study tool and are not affiliated with the Bundesamt für Migration und Flüchtlinge (BAMF), telc, the g.a.s.t. institute, or any German public authority.

1. Information we collect

Account & purchase data

• Email address — collected when you start a trial or purchase DTZ access (a 1-month pass, 3-month pass, or lifetime access). Used solely to validate your entitlement and send receipts. The free Einbürgerungstest part of the app can be used without providing an email.
• Payment information — processed entirely by Apple (iOS in-app purchases, via RevenueCat) or Stripe (web). We never see or store your card number, CVV, or full payment details.

Usage data (stored locally on your device)

• Your training progress, session history, mastered items, exam-simulation scores, profile name, chosen Bundesland (federal state), target exam date, and daily-goal targets.
• This data is stored in your device's local storage and never transmitted to our servers unless you switch on the optional cloud backup (below).

AI-judge data (DTZ Schreiben / Sprechen grading)

• For the DTZ writing (Schreiben) and speaking (Sprechen) tasks, when you ask for feedback we send your answer plus the task context to Anthropic's Claude API for grading.
• We do not store these submissions on our servers. Anthropic processes them under its own data policy.
• We do not link your AI submissions to your identity.

Technical / device info

• App version, OS version, device type, language preference, and a random anonymous device identifier — used anonymously to de-duplicate analytics events and for crash reporting / product improvement. This identifier is not linked to your name or email.

Optional cloud backup (only if you turn it on)

• If you enable cloud backup/sync, your training progress is stored on our server so it survives reinstalling the app or moving to a new device. It is keyed to a hash of your email (we do not store your email in readable form for this purpose) and stores only your app progress, never payment details. You can turn it off any time in Settings.

Anonymous usage analytics

• We use privacy-friendly, cookieless first-party analytics to count anonymous visits, page views, and a few product events (e.g. trial started, app installed, purchase completed). These counts are aggregated and anonymous, stored in our own EU-hosted key-value store; they do not identify you and use no advertising or cross-site tracking cookies.

Microphone (speech-recognition feature)

• The app includes an optional speech-recognition feature for the DTZ speaking (Sprechen) practice. You can always type your answer instead.
• When you tap the microphone button, the app requests microphone permission. You can decline; the rest of the app works without it.
• Speech recognition is performed by your browser or operating system using the standard Web Speech API. We do not store or transmit your audio recordings to our servers.
• On Chrome (Android/desktop) recognition typically runs locally on your device. On iOS Safari, Apple performs the recognition via its operating-system speech service (see Apple's privacy policy for details). We have no access to the audio either way.
• Only the recognized text (the transcript — not audio) is used by your device to fill in or match your answer. It is not retained or transmitted by us beyond the AI-grading flow described above.

Information we do NOT collect

• We do not collect location data.
• We do not access your contacts, photos, or camera.
• We do not store microphone audio on our servers (see above for how speech recognition works).
• We do not use third-party advertising trackers.
• We do not sell, rent, or share your data with third parties for marketing.

2. How we use your information

• Email: send purchase receipts; validate your trial/pass/lifetime entitlement; respond to support requests.
• Payment data: process purchases via Apple/RevenueCat or Stripe (per their privacy policies).
• Usage data (local): power the training features on your device. Never leaves your device unless you enable cloud backup.
• AI submissions: provide answer grading for the DTZ Schreiben/Sprechen tasks. Not retained by us.
• Anonymous telemetry: improve the product, fix crashes.

3. Legal basis (GDPR/DSGVO Article 6)

• Performance of a contract (Art. 6(1)(b)): processing your email and entitlement is necessary to deliver the paid DTZ features you purchased.
• Legitimate interest (Art. 6(1)(f)): anonymous, aggregated analytics and crash reporting help us deliver a stable product.
• Consent (Art. 6(1)(a)): optional features such as cloud backup and crash reporting are opt-in and can be withdrawn at any time.

4. Data retention

• Email + entitlement: retained as long as your account/entitlement is active, plus the statutory retention period required for tax and accounting compliance under the law of the operator's country of establishment (currently up to 7 years).
• Usage data: stored on your device until you delete the app or clear browser data; not held by us (unless cloud backup is on, in which case you can delete it in Settings).
• AI submissions: not retained by us. Anthropic's retention is governed by its policy.
• Payment records: retained by Apple/RevenueCat/Stripe per their policies; we keep only transaction/entitlement identifiers.

5. Your rights (GDPR/DSGVO)

You have the right to:

• Access the data we hold about you (essentially your email + entitlement record).
• Rectify inaccurate data.
• Erase your data ("right to be forgotten"). On request, or via Settings → Delete account, we delete your entitlement record; your local device data you can wipe via Settings → Reset.
• Restrict processing.
• Data portability — receive your data in a structured format.
• Object to processing.
• Withdraw consent at any time (for opt-in features).
• Lodge a complaint with a data protection authority. You may contact the authority in your country of residence — in Germany, the competent Landesdatenschutzbehörde or the Bundesbeauftragte für den Datenschutz und die Informationsfreiheit (BfDI, bfdi.bund.de). As the operator is established in the Netherlands, our lead supervisory authority is the Dutch Autoriteit Persoonsgegevens (autoriteitpersoonsgegevens.nl).

To exercise any right, email us at kell@chefzwart.nl. We respond within 30 days.

6. Third-party processors

The following sub-processors handle limited data on our behalf:

Processor	Data handled	Purpose	Location
Vercel	Email (in transit), API requests	Web/app hosting	EU / USA
Upstash	Hashed email, entitlement record, anonymous counters	Entitlement & analytics storage (key-value)	EU
RevenueCat	Apple transaction/entitlement identifiers	iOS in-app-purchase entitlement management	USA
Apple (iOS)	App Store account, payment	iOS in-app purchases	per Apple privacy policy
Stripe	Email, payment method	Web payment processing	EU / USA
Anthropic	Submitted answer text (DTZ Schreiben/Sprechen)	AI grading	USA
Sentry (optional)	Anonymous crash data	Stability monitoring	EU

Where processing involves a transfer outside the EU/EEA, we rely on the EU Standard Contractual Clauses (SCCs) as the transfer mechanism (GDPR Art. 46).

7. Children

The app is intended for adults preparing for the German naturalisation test (Einbürgerungstest) and the DTZ. We do not knowingly collect data from anyone under 16. If you believe a minor has provided us data, contact us and we will delete it.

8. Security

• All traffic is encrypted in transit (HTTPS / TLS 1.2+).
• Payment processing is PCI-compliant via Apple/RevenueCat/Stripe.
• Local device data is stored in standard browser/app storage (not separately encrypted by us at rest).
• We follow industry best practices but cannot guarantee perfect security.

9. International transfers

Some of our processors (Vercel, RevenueCat, Anthropic, and possibly Stripe) may process data in the USA. We rely on the EU Standard Contractual Clauses (SCCs) as the transfer mechanism under GDPR Art. 46.

10. Changes to this policy

We may update this Privacy Policy. The "Last updated" date at the top reflects the most recent change. Material changes will be communicated via in-app notice or email.

11. Contact

Questions about this policy? Email: kell@chefzwart.nl

This policy is governed by the law of the operator's country of establishment (the Netherlands). This does not deprive you of the mandatory data-protection rights guaranteed to you by the GDPR/DSGVO in your country of residence.