EU Privacy Policy

Privacy Policy for users in Europe (GDPR)

Last updated: September 24, 2026

This policy explains how DeepChinese ("we", "us") processes personal data when you use our app or website in the European Economic Area, the United Kingdom or Switzerland, in accordance with the General Data Protection Regulation (GDPR), the UK GDPR and applicable national law.

1. Data controller

DeepChinese is the data controller for the limited processing described below. Contact us about anything privacy-related atprivacy@deepchinese.nl.

2. Local-first by design, accounts optional

The app is built so that your learning data — favorites, flashcard lists, study settings, reminders and progress — is created and kepton your own device. You can use every feature without an account, and we operate no login wall: signed out, nothing about your study leaves your device.

Creating an account is an opt-in backup and syncfeature. If you choose to use it, copies of the study data listed in §3 are sent to our backend so the same progress appears on your other devices, and your Pro purchase can follow you. If you never sign in, that processing simply never happens.

3. Where your data is hosted

The account backend — sign-in and the study-data database — is hosted inSwitzerland. The European Commission has adopted anadequacy decision for Switzerland under Art. 45 GDPR, recognising a level of protection essentially equivalent to the GDPR, so no further transfer safeguard (such as the Standard Contractual Clauses) is required for that storage. We publish the country, not the infrastructure: we do not list the provider, the datacentre or the specific services behind it. If you need the processor's identity — for a complaint or a filing with your supervisory authority — ask at the address in §1 and we will provide it.

Data that is not part of your account stays where it was created: on your device. Reminder times and notification consent, per-deck study options and session history are deliberately device-local and are not synced.

4. Personal data we process, purposes and legal bases

• Account credentials — your e-mail address, used to send a one-time sign-in code (no password is stored), or the identifier from Google/Apple sign-in where offered. Purpose: creating and securing your account; legal basis: performance of a contract (Art. 6(1)(b)) and consent (Art. 6(1)(a)) when you sign in.
• Synced study documents — favorites, spaced-repetition progress, Deep Drill and HSK-practice results, flashcard lists and three preferences (theme, app language, character style), stored as documents keyed to your account. Purpose: keeping your progress available on your devices; legal basis: Art. 6(1)(b) and consent.
• Device identifier — a random identifier generated on each install, sent with each synced change so that edits made on two devices offline can be merged deterministically. It is not used to track you and identifies no person outside your own account.
• Profile fields — an optional display name, plus account created and last-seen timestamps.
• Purchase information — Pro subscription status shared by the Apple App Store, Google Play or our payment provider, mirrored server-side so entitlement can be checked and support can answer "did this person pay". Purpose: unlocking and restoring features you paid for; legal basis: performance of a contract (Art. 6(1)(b)) and legal obligations for accounting and tax records (Art. 6(1)(c)). We never see or store your full payment details.
• Support correspondence (message contents and contact details you provide) — purpose: answering your request; legal basis: legitimate interests (Art. 6(1)(f)) and, where you consent by contacting us, consent (Art. 6(1)(a)).
• Product analytics — aggregate usage events sent to our product-analytics provider, which processes them on infrastructure located in the European Economic Area, to see which features are used. The same provider receives error and crash reports when the app runs into a problem, so we can find and fix defects. Analytics is anonymous by default; if you create an account, events may be linked to your account identifier so we can tell signed-in usage apart, and the link is removed when you delete the account. Legal basis: legitimate interests (Art. 6(1)(f)).
• Website language preference, stored in your browser's local storage when you visit deepchinese.nl — purpose: remembering your language choice; legal basis: legitimate interests (Art. 6(1)(f)). Our website sets no tracking cookies and uses no third-party advertising.

5. Who else touches your data

We share data only where necessary, and each recipient acts as a processor on our instructions:

• Our account-hosting provider — sign-in and database hosting, in Switzerland.
• Our payment provider — purchase validation and entitlements.
• Our product-analytics provider — usage events and error/crash reports, on EEA infrastructure.
• Google Play / Apple App Store — payment processing; they are controllers for your store account and purchase history.
• Our mail provider, for support correspondence and sign-in codes.

Because non-account learning data stays on your device, it is not transferred to anyone. Where a recipient is located outside the EEA and no adequacy decision applies, transfers rely on appropriate safeguards such as the EU Standard Contractual Clauses.

6. Retention

• On-device learning data: kept until you delete it or uninstall the app.
• Account data and synced documents: kept while your account exists, and deleted with it (see the deletion page).
• Support messages: kept only as long as needed to handle your request.
• Purchase and accounting records: kept as long as tax and commercial law requires.
• Encrypted database backups: overwritten as backup cycles expire; personal data deleted from the live database is not restored from them.

7. Your rights

Under the GDPR you have the right to:

• Access (Art. 15) — obtain confirmation and a copy of your data.
• Rectification (Art. 16) — correct inaccurate data.
• Erasure (Art. 17) — have your data deleted where the conditions apply.
• Restriction (Art. 18) — limit how we process your data.
• Portability (Art. 20) — receive data you provided in a portable format.
• Object (Art. 21) — object to processing based on legitimate interests, including the analytics above.
• Withdraw consent (Art. 7(3)) — where processing is based on consent, such as signing in.

To exercise any right, emailprivacy@deepchinese.nl. For erasure, step-by-step instructions — including what we delete, what we keep and for how long — are on ouraccount deletion page; you can also delete your account directly in the app under Settings → Account. We will respond without undue delay and within one month at the latest. If you are unhappy with our response, you may lodge a complaint with your national data protection supervisory authority.

8. Children

DeepChinese is not directed at children, and we do not knowingly process children's personal data. If you believe a child has sent us personal data, contact us and we will delete it.

9. Security

On-device data benefits from your device's own protections (such as screen lock and encryption). Server-side account data is reached only over TLS, and row-level security in the database means an authenticated client can read and write only its own rows; a signed-out client can read none of them. Keys that can bypass those rules are held only in server-side functions and never ship inside the app. Support correspondence is handled with appropriate technical and organizational measures and accessed only as needed to help you.

10. Changes to this policy

If we change this policy, the updated version will be posted here with a new "Last updated" date. Material changes will additionally be highlighted in the app where appropriate.

11. Contact

Privacy questions or requests:privacy@deepchinese.nl.

Visiting from the United States? Read ourUS Privacy Policy instead.