Legal

Privacy Policy

Last updated: August 3, 2026

This Privacy Policy explains how Chénjìn 沉浸 ("Chénjìn," "we," "us," or "our") collects, uses, shares, and protects information when you use our website, our mobile app, our browser extension, and related services (collectively, the "Service"). By using the Service, you agree to the collection and use of information as described in this policy. Sections 5 and 6 describe practices specific to the mobile app and the browser extension.

1. Information We Collect

Account information

When you create an account, we collect your email address and password (handled securely by our authentication provider, Supabase) and any profile details you choose to add, such as a display name, avatar, bio, native-speaker status, or self-reported HSK level.

Content you provide

• Text, audio, and YouTube links you upload to build reading/listening lessons
• Comments, community posts (including images you attach to them), replies, and votes
• Reader notes, sentence translations you save, and suggested edits to articles
• Reports you file and support messages you send us (including through the Contact form)

Learning and usage data

To power features like spaced-repetition flashcards, progress tracking, and recommendations, we record your vocabulary state (known/learning/unknown), flashcard review history, reading and listening activity, dictation/cloze results, game and exercise attempts, contribution points, and similar in-app activity.

Audio recordings

If you use a pronunciation feature — Tone Coach, pronunciation practice, voice dictation, or voice-based games, on the website or in the mobile app — we temporarily process a recording of your voice to score your pronunciation. These recordings are analyzed by our speech-scoring provider (Microsoft Azure) and we keep the resulting scores, not the recordings themselves. If you upload native-speaker reference audio to Tone Coach, short word-level excerpts of that audio may be added to a shared pronunciation-reference library that other learners can play; the upload screen describes the rights you must hold in that audio.

If you use sentence mining (Video Study on the website, or the browser extension), the audio clips and images you create from a video are stored in your account so you can review them later, and are deleted if you delete your account.

Push notification tokens (mobile app)

If you allow notifications in the mobile app, we store a device push token so we can send you notifications such as flashcard-review reminders and community activity. The token is removed when you sign out, and you can disable notifications at any time in your device settings.

Payment information

Subscription payments made on our website are processed directly by Stripe, our payment processor. Subscriptions purchased in the mobile app are processed by Apple's App Store or Google Play and managed through RevenueCat, our in-app purchase platform. In all cases we do not receive or store your full card number. We retain your subscription tier, billing status, and a customer/subscription reference (Stripe, or RevenueCat/app-store equivalents) so we can manage your plan.

Device and log data

Like most web services, our servers automatically log standard technical information such as IP address, browser type, and request timestamps, used for security, debugging, and abuse prevention.

Cookies and tracking technologies

We use the following categories of cookies and similar technologies:

• Strictly necessary — keep you signed in, protect your account, and remember preferences you set directly (such as your text-to-speech voice). These cannot be switched off without breaking core functionality.
• Analytics — we use Google Analytics to understand how visitors use the Service (pages visited, general usage patterns) so we can improve it.
• Advertising — we plan to use advertising and remarketing tools such as Google Ads and Meta (Facebook/Instagram) Ads to measure ad performance and show relevant ads on other sites.

Where required by law — including for visitors in the European Economic Area, the United Kingdom, and other regions with similar requirements — we request your consent via a cookie banner before activating analytics or advertising cookies, and you can change your choice at any time. California residents may opt out of the "sale or sharing" of personal information for cross-context behavioral advertising; see Section 8 below. These cookie categories apply to our website; the mobile app and browser extension do not contain advertising or analytics trackers (see Sections 5 and 6).

2. How We Use Information

• To provide, operate, and maintain the Service, including your reading progress, flashcards, and personalized recommendations
• To process subscription payments and manage billing
• To generate AI-assisted features you request, such as example sentences, translations, transcriptions, and pronunciation scoring
• To send you account, billing, and security emails, and — if you opt in — product updates, learning tips, a community digest, or promotions (see Settings → Email Preferences)
• To send you push notifications you have allowed in the mobile app, such as flashcard-review reminders and community activity
• To moderate community content, investigate reports, and enforce our Terms of Service
• To respond to support requests submitted through the Contact form
• To improve and develop new features

3. AI and Third-Party Processing

We use OpenAI's API to generate translations, example sentences, and sentence-mining suggestions, and Microsoft Azure's Cognitive Services to provide text-to-speech audio, pronunciation scoring, and audio transcription. The specific text or audio needed to perform these tasks is sent to these providers and is handled subject to their own privacy and data-processing terms. We do not control how these third parties secure data beyond our contractual terms with them, and we do not use your content to train our own machine-learning models. The mobile app's camera text-recognition feature runs entirely on your device (using Google ML Kit) — camera images are never sent to us or to any third party; only the recognized text you tap is sent to our servers to perform a dictionary lookup.

4. How We Share Information

We do not sell your personal information. We share information only in the following circumstances:

• Service providers — Supabase (database, authentication, file storage), Stripe (website payments), Apple, Google, and RevenueCat (mobile in-app purchases), OpenAI and Microsoft Azure (AI features described above), Loops.so (transactional and, if you opt in, marketing email), Expo (delivery of mobile push notifications), and Sentry (crash reporting in the mobile app, if enabled — crash reports may include your device model, operating system version, and app state at the time of the error, and are used only to diagnose and fix bugs)
• Analytics and advertising partners — Google (Google Analytics, and in the future Google Ads) and, in the future, Meta (Facebook/Instagram Ads), who receive information via cookies as described in Section 1, subject to your cookie consent choices where required
• Public content — anything you choose to make public, such as a public profile, public uploads, comments, community posts, and contributions, is visible to other users and visitors
• Legal reasons — if required by law, legal process, or to protect the rights, property, or safety of Chénjìn, our users, or others
• Business transfers — in connection with a merger, acquisition, or sale of assets, subject to this policy continuing to apply to your information

5. The Chénjìn Mobile App

The mobile app signs in to the same Chénjìn account and talks to the same servers as the website, so everything above applies to it. The following practices are specific to the app:

• Microphone — used only when you start a pronunciation feature (Tone Coach, voice dictation, or voice games). Recordings are sent to our servers for scoring as described in Section 1 and are not used for any other purpose.
• Camera — used only for the text-scanner feature. Text recognition happens entirely on your device; camera images never leave your phone (see Section 3).
• Photo library — accessed only when you choose a photo, either to scan it for Chinese text on-device or to attach it to a community post. Photos attached to public posts are uploaded to our storage and visible to other users.
• Push notifications — optional; see Section 1. Notifications are delivered through Expo's push service and Apple/Google's notification systems.
• In-app purchases — handled by Apple's App Store or Google Play with RevenueCat, as described in Section 1. Manage or cancel app subscriptions through your app-store account settings.
• Local storage — the app stores your session and cached content (such as recently viewed articles, vocabulary states, and your scanner lookup history) on your device so it loads quickly. This data stays in the app's private storage and is removed when you delete the app.
• Stroke-order animations — character stroke data is loaded from a public content-delivery network (jsDelivr), which receives standard request information such as your IP address.
• No advertising or analytics — the app contains no advertising SDKs, no analytics trackers, and no advertising identifiers. Video Study plays YouTube videos in an embedded player, which is subject to YouTube's own terms and privacy policy.

You can delete your account and associated data at any time from the website (Settings → Account → Danger Zone) or by contacting us; deletion applies to your account across the website, the app, and the extension.

6. The Chénjìn Browser Extension

The browser extension brings dictionary lookups, subtitle enrichment, and sentence mining to video and reading sites you already use. It authenticates using your existing Chénjìn login session in the browser and stores no passwords or tokens of its own. It contains no analytics or tracking, loads no remote code, and communicates only with our servers, the video service you are watching, and (optionally) Anki on your own computer. Specifically:

• Subtitles and captions — on supported video sites, the extension reads the video's subtitle track (retrieving it from the video service you are watching) and sends the lines to our servers so we can add pinyin, definitions, and your vocabulary status. Subtitle text for a video may be cached on our servers so it loads faster for other learners studying the same video; this cache contains the video's subtitles, not anything about you.
• Sentence mining — when you mine a sentence, the extension sends us the selected text (expanded to the full surrounding sentence), and — for video mining — a short audio clip and an image of the video frame at that moment. On non-video pages, you can optionally include a screenshot of the visible page; if capturing just the video frame is blocked by the site, a screenshot of the visible tab may be used instead. Mined cards also record the site or video they came from so you can see the source later. All of this is stored in your account.
• Where it runs — the extension's features activate on the supported sites listed in its store listing and, for the page-mining feature, on any page where you explicitly invoke it (via the right-click menu or the extension popup). It does not read pages in the background.
• Local storage — preferences (such as pinyin display and overlay position) and a record of which subtitle lines you have already mined are stored locally in your browser.
• Anki sync — if you set your flashcard destination to Anki, cards are sent directly from your browser to the Anki app running on your own computer; this data never passes through our servers. (The website's Anki sync option works the same way.)

7. Data Retention

We retain your information for as long as your account is active or as needed to provide the Service. If you delete your account (Settings → Account → Danger Zone), we permanently delete your account and associated personal data, cancel any active subscription, and remove your contact record from our email system. Some information may be retained where required by law (for example, billing records) or where it has already been aggregated/anonymized.

8. Your Rights and Choices

• Access and update most of your profile and learning data directly within the app
• Adjust marketing email categories any time in Settings → Email Preferences, or unsubscribe via the link in any marketing email
• Delete your account and associated data at any time via Settings → Account → Danger Zone
• Request a copy of, correction to, or deletion of your information by emailing us at admin@chenjinmandarin.com or using our Contact form
• Manage or withdraw consent for analytics and advertising cookies at any time via our cookie banner

If you are located in the European Economic Area, the United Kingdom, or California, you may have additional rights under laws such as the GDPR or the CCPA, including the right to access, correct, delete, or port your information, and to object to or restrict certain processing. We honor these rights for all users on request, regardless of location. California residents specifically have the right to opt out of the "sale or sharing" of personal information for cross-context behavioral advertising (relevant once our advertising cookies described in Section 1 are active) — use the cookie banner, your browser's Global Privacy Control signal if supported, or contact us directly.

9. Children's Privacy

The Service is not directed to children under 13, and we do not knowingly collect personal information from children under 13. If you believe a child under 13 has provided us with personal information, please contact us and we will delete it.

10. International Data Transfers

Our infrastructure and service providers are primarily located in the United States. If you access the Service from outside the United States, your information will be transferred to, stored, and processed in the United States, where data protection laws may differ from those of your country.

11. Security

We use reasonable technical and organizational measures to protect your information, including encryption in transit and database access controls (row-level security on sensitive tables). No method of transmission or storage is completely secure, and we cannot guarantee absolute security.

12. Third-Party Links

The Service may link to or embed third-party content, such as YouTube videos used in Video Study on the website and in the mobile app. We are not responsible for the privacy practices of third-party sites or services, and we encourage you to review their privacy policies.

13. Changes to This Policy

We may update this Privacy Policy from time to time. We will post the updated policy on this page with a new "Last updated" date, and where changes are material, we will provide additional notice (such as an email or in-app notice).

14. Contact Us

If you have questions about this Privacy Policy or how we handle your information, contact us at admin@chenjinmandarin.com or via our Contact page.