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Privacy Policy

Last updated: April 19, 2026

Introduction

HAN•GL ("we," "our," or "us") is committed to protecting your privacy. This Privacy Policy explains our data practices for the HAN•GL mobile application and website.

By default, HAN•GL works anonymously: you can use the app without creating an account, providing an email, or sharing your name. Cloud backup is optional and user-initiated.

Data Controller

The data controller responsible for processing your data is:

Kevin Myung
Fehmarnerstrasse 17
13353 Berlin, Germany
hello@hangl.app

What We Collect

HAN•GL collects the minimum data required to deliver the app and improve it over time. We do not sell data, do not show advertisements, and do not track your location.

Anonymous mode (default):

  • An anonymous user ID generated by Firebase Authentication. This ID is a random string — not linked to you personally.
  • Your learning progress (chapters completed, vocabulary collected, mastery levels, quiz scores) synced to Firebase Cloud Firestore under this anonymous ID. This enables progress recovery if you reinstall the app.
  • Anonymized analytics and crash reports (see "Analytics and Usage Data" below).

When you link your account (optional):

  • Your email address, as provided by Apple Sign-In or Google Sign-In. You can hide your real email via Apple's "Hide My Email" feature, in which case we only receive a relay address.
  • A permanent user ID that replaces your anonymous ID. Your progress is still stored under this ID so it can follow you across devices.

We do NOT collect:

  • Your name, phone number, address, or any other contact information
  • Your location or GPS coordinates
  • Photos, contacts, microphone input, or other personal files
  • Advertising identifiers (we explicitly disable the Android AD_ID permission)

Authentication & Accounts

HAN•GL uses Firebase Authentication (a Google service) to manage user identities.

On first launch, the app signs you in anonymously — no personal data is collected, just a random device-scoped ID. If you choose to link your account via Apple Sign-In or Google Sign-In, Firebase issues a permanent ID tied to your Apple or Google identity, and we receive your email address.

Legal basis: Contract performance (Art. 6(1)(b) GDPR) — anonymous authentication and cloud backup are necessary to deliver the core app service (your progress surviving reinstalls and cross-device sync).

You can review Firebase Authentication's privacy practices at firebase.google.com/support/privacy.

Cloud Sync

Your learning progress is stored locally on your device and synced to Firebase Cloud Firestore under your user ID (anonymous or permanent). This sync enables progress recovery if you reinstall the app and cross-device continuity if you link your account.

What is synced:

  • Completed chapters, lessons, and tests
  • Vocabulary collected and mastery levels
  • App flags (e.g. which intros you've seen)

What is NOT synced: language preference, UI toggles, and other device-local settings stay on your device only.

Legal basis: Contract performance (Art. 6(1)(b) GDPR).

Cloud Functions

HAN•GL uses a small number of Firebase Cloud Functions (server-side code running on Google's infrastructure) for two purposes:

  • mergeAnonymousProgress — when you sign in to an Apple or Google account that already has HAN•GL progress, this function combines your current device's progress with the existing cloud record so nothing is lost.
  • deleteAccount — when you delete your account from Settings, this function removes your Firestore record and your Firebase Auth user. No trace is kept on our side.

These functions run on demand (triggered by your actions) and do not store additional data beyond what is already in Firestore.

Account Deletion

You can delete your account at any time from the app: Menu → Login / Signup → Delete account. Deletion is immediate and permanent — no grace period. On deletion:

  • Your Firestore progress record is deleted.
  • Your Firebase Authentication user is deleted.
  • Analytics data (anonymized and not linked to your identity) continues its normal retention period of 14 months.
  • Your subscription, if any, is not cancelled — it is managed by Apple or Google outside of our control, and you should cancel it separately via your App Store or Play Store account if desired.

To delete data collected via our waitlist (prior to launch) or any other request, email hello@hangl.app.

Analytics and Usage Data

To improve the app experience and fix technical issues, we collect anonymized usage data and crash reports through Firebase Analytics and Firebase Crashlytics (services provided by Google). This data is keyed to your Firebase user ID, which is not linked to your real identity.

Legal basis: Legitimate interest (Art. 6(1)(f) GDPR) — we have a legitimate interest in understanding how users interact with the app and in maintaining its stability. This processing is minimal, anonymized, and does not override your rights.

What we collect:

  • App usage patterns (which chapters, lessons, and vocabulary levels you view, quiz scores, time spent in the app)
  • Crash logs and error reports to help us identify and fix bugs
  • General device information (device model, operating system version)

How we use this data:

  • Understand which features users find most helpful
  • Identify and fix crashes and technical errors
  • Improve the overall app experience
  • Make decisions about future content and features

Important: This analytics data is NOT used for advertising, NOT sold to third parties, and NOT linked to your personal identity. It is aggregated and used solely to improve the app.

Retention: Analytics data is retained in Firebase for 14 months, after which it is automatically deleted. Crash reports are retained for 90 days.

Purchases and Subscriptions

If you make a purchase or subscribe to HAN•GL, payment processing is handled entirely by Apple (App Store) or Google (Google Play). We do not collect or store your payment information (credit card numbers, billing address, etc.).

We use RevenueCat to manage subscription status across platforms. RevenueCat receives:

  • A RevenueCat user ID (not linked to your real identity or your Firebase ID)
  • Transaction identifiers provided by Apple or Google
  • Subscription status (active, expired, cancelled)
  • Product and pricing information for your purchase

Legal basis: Contract performance (Art. 6(1)(b) GDPR) — this processing is necessary to deliver the subscription service you purchased.

RevenueCat acts as a data processor on our behalf. You can review RevenueCat's privacy policy at https://www.revenuecat.com/privacy.

Third-Party Services

HAN•GL uses the following third-party services as data processors:

Firebase (Google):

  • Firebase Authentication — Anonymous user IDs by default; permanent IDs when you link Apple or Google
  • Firebase Cloud Firestore — Stores your learning progress so it survives reinstalls
  • Firebase Cloud Functions — Runs the account-merge and account-delete operations on our servers
  • Firebase Analytics — Tracks anonymous usage patterns and app interactions
  • Firebase Crashlytics — Monitors app crashes and errors to help us fix bugs

Apple Sign-In (optional):

  • Provides your email address (or an Apple-relayed email) and a unique identifier. Used only to link your account to your progress.

Google Sign-In (optional):

  • Provides your email address and a unique identifier. Used only to link your account to your progress.

RevenueCat:

  • Subscription management — Manages purchase verification and subscription status

Data Security: All data transmitted to these services is encrypted in transit. Firebase data is stored on Google's servers subject to Google's security standards. You can learn more at firebase.google.com/support/privacy.

We do not share your data with any advertising networks, data brokers, or other third parties beyond those listed above.

International Transfers

Firebase and RevenueCat process data on servers located in the United States and other regions. Google and RevenueCat rely on Standard Contractual Clauses (SCCs) and other safeguards approved by the European Commission to transfer data out of the EU. By using the app, you acknowledge that your data may be processed outside your country of residence.

Your Rights (GDPR)

Under the General Data Protection Regulation (GDPR), you have the following rights regarding your data:

  • Right of access — You can request a copy of any data we hold about you
  • Right to rectification — You can request correction of inaccurate data
  • Right to erasure — You can delete your account in-app (Menu → Login / Signup → Delete account), or email us
  • Right to restrict processing — You can request that we limit how we use your data
  • Right to data portability — You can request your data in a machine-readable format
  • Right to object — You can object to processing based on legitimate interest

To exercise any of these rights, contact us at hello@hangl.app and we will respond within 30 days.

You also have the right to lodge a complaint with a supervisory authority. The relevant authority for us is the Berliner Beauftragte für Datenschutz und Informationsfreiheit (datenschutz-berlin.de).

Children's Privacy

HAN•GL is suitable for learners of all ages and works anonymously by default — no name, email, or other personal information is collected in anonymous mode.

Account linking is restricted to users aged 16 and over. Linking your progress to an Apple or Google account requires us to receive an email address from the provider. Under Art. 8 GDPR, processing personal data of children under 16 in Germany requires verifiable parental consent, which we do not currently offer. Children under 16 may continue to use HAN•GL in anonymous mode without restriction.

If you become aware that a child under 16 has linked an account, please contact us at hello@hangl.app and we will delete the account promptly. Parents may also use the in-app Delete Account flow at any time.

We comply with the Children's Online Privacy Protection Act (COPPA) for users in the United States and equivalent children's privacy laws in other jurisdictions. The anonymized analytics we collect is not linked to any individual user and is used solely to improve the app.

Website

Our website (hangl.app) does not use analytics, tracking pixels, or advertising cookies. No personal data is collected from website visitors. The site is hosted by Netlify, which may process technical request metadata (IP address, user agent, request timestamp) in standard server logs for security and infrastructure purposes.

Waitlist

If you joined our waitlist prior to app launch, we collected your email address, platform preferences, and primary language solely to notify you when HAN•GL became available. This data is stored in a private Google Sheet and is not shared with third parties. You may request deletion of this data at any time by contacting us.

Changes to This Policy

We may update this Privacy Policy from time to time. We will notify you of any changes by posting the new Privacy Policy on this page and updating the "Last updated" date.

Contact Us

If you have questions about this Privacy Policy, please contact us at hello@hangl.app