Privacy Policy

This Privacy Policy explains how Vocabden ("we," "us," or "our") collects, uses, shares, and protects personal data when you use our four products: the Vocabden mobile application (the "App"), the MusicDen mobile application ("MusicDen"), the TranslateDen mobile application ("TranslateDen") and the Vocabden browser extension (the "Extension"). Together, the App, MusicDen, TranslateDen and the Extension are referred to as the "Services."

The App helps users learn languages through stories, songs, listening exercises, flashcards, short educational video excerpts paired with vocabulary exercises, progress tracking, and AI-powered language analysis. The Extension lets you select a word, phrase, or sentence on any website — or from subtitles while watching supported video and streaming platforms — and receive an instant AI-powered analysis or translation that you can save to your vocabulary. MusicDen teaches languages through song games: you listen to a song, fill in its lyrics, look up words and phrases from the song, and compare your scores with other players. TranslateDen translates a word, a sentence or a paragraph between languages, shows what a tapped word means in that sentence, saves the words you look up and lets you review them with flashcards; its Den keyboard translates what you type inside other apps.

All four products use the same Vocabden account and the same backend, so your saved words and learning progress stay in sync. If you sign in to MusicDen or TranslateDen with an existing Vocabden account, that app uses the same account; you do not create a second one. A Lens, Plus or Pro subscription bought in the App, in MusicDen or in TranslateDen is valid in all three apps. Deleting your account deletes it from all four products (see Section 12). By using the Services, you agree to the practices described in this Privacy Policy.

1. Information We Collect

We may collect the following types of information across the Services. Where a practice applies to only one product, we say so.

a. Account and identity information

• Name
• Username
• Email address
• Login credentials
• Profile information

When you sign in to the Extension with Google, we receive your Google account's email address, name, and basic profile information in order to create or access your Vocabden account.

b. Learning and usage data

• Selected learning language(s)
• Completed lessons, stories, and exercises (App)
• Vocabulary learning status and saved words
• Learning progress and performance statistics
• Streak and study activity data
• In-app interactions and usage history
• Video excerpt viewing data (which excerpts were viewed, viewing duration) (App)
• Exercise performance data associated with video excerpts (responses, accuracy, time spent, hints used) (App)
• Video playback interaction data (play, pause, replay actions) (App)
• Den practice sessions: the word you practise, the step you have reached, when the next review is due, and the automatic evaluation result of each attempt (App; see Section 1.g)

c. Data collected through the browser extension

When you actively use the Extension, we process:

• Words, phrases, sentences, or text you select on a web page and choose to analyze, translate, or save
• Subtitle text from supported video and streaming platforms when you enable the Extension's translation or overlay features, so we can show translations and word analysis
• The vocabulary you save and your learning preferences (such as your native and target language)
• A session token and your settings, which the Extension stores locally in your browser's extension storage to keep you signed in

The Extension processes only the text you actively select, or the subtitles on a page where you turn the feature on. It does not read, collect, or transmit your general browsing history, the full content of the pages you visit, your keystrokes, passwords, or form data.

d. Technical information

• Device or browser model
• Operating system version
• App or extension version
• Crash logs and error reports
• Performance and diagnostic data
• IP address or similar network information

e. Payment and subscription information

If the Services offer paid features or subscriptions, payments may be processed through the Apple App Store, Google Play, or third-party payment providers.

We do not directly store full payment card details. However, we may process limited transaction-related data such as subscription status, purchase verification, and billing-related records as necessary to provide the service.

f. Content processed through AI features

When you use AI-powered features in the App, TranslateDen or the Extension — such as analysis, translation, or explanations — the words, phrases, sentences, paragraphs, subtitle lines, or other language content you submit are sent to our servers and AI providers in order to generate the result you requested.

g. Den practice and the automatic evaluation of your sentences

When you practise a word with Den in the App (for example, by tapping "Help me make a sentence" on a word card), the sentence you write is sent to our AI provider together with the word and the card's meaning. While preparing its reply, Den also automatically evaluates whether your sentence uses the word correctly.

From this practice we store:

• The state of the practice: which word you are practising, the step you have reached, and when the next review is due.
• The result of each attempt: a label such as "correct", "correct after the correction" or "mistake"; whether the word appears in your sentence; whether you opened a hint, another example or a simpler explanation; and a measure of whether the sentence was copied from the example shown on screen. Attempt records do not contain the sentence you wrote.
• The last correction: the part of your sentence that Den corrected (up to 200 characters), the corrected version and a short reason, so that Den can remind you of the same point in your next session.

These results only decide the result line you see, what Den asks you next, and when the word comes back for review. They do not produce decisions with legal or similarly significant effects on you: they do not change your access to a service, your price, or your account status.

If you think an evaluation is wrong, tap "The evaluation is wrong" in the practice panel to remove that attempt from your results; your results are recalculated without it. The disputed attempt is kept, marked as disputed, only so that we can measure how accurate the evaluation is. "Delete this practice" deletes the practice and all of its results. You can also exercise your rights in Section 11 at any time.

h. Data collected through MusicDen

MusicDen uses the same account, learning and technical data described above. In addition, when you use MusicDen we process:

• A guest account: MusicDen can be used without signing in. We then create an anonymous account tied to your device that stores your languages and game results. If you later create an account or sign in, the guest account's data is moved into that account.
• Learning and translation languages: the languages you learn in MusicDen and the language you want translations in.
• Song game results: the songs you play, the difficulty you choose, your answers, your score and your daily game count.
• Player name: the name you enter after a song so that your score can appear on leaderboards. Your player name and score are visible to other users on the MusicDen and Vocabden leaderboards and on the music pages of our website. Do not use your full name or other personal information as your player name.
• Song requests: the song title and artist you ask us to add, so that we can tell you when the song is ready.
• Words and phrases you save from songs.

Achievement card: MusicDen asks for access to your photo library only when you choose to save an achievement card to your photos. It only adds that image; it does not view or read your existing photos. If you share the card, it is sent only to the app you choose in your phone's share menu.

Notifications: if you allow notifications, MusicDen receives notifications about songs, for example when a song you requested is ready. Notifications from the App and from MusicDen are coordinated: a notification is sent to only one of the two apps, so you do not receive the same notification twice. Music notifications go to MusicDen if you have allowed notifications there; otherwise they go to the App.

Usage analytics: like the App, MusicDen sends usage events to Mixpanel and Firebase Analytics, such as which screens you open, which songs you play and which buttons you tap, together with your account ID, app version, device model and interface language. We use these events to understand which features work and to fix problems. We do not collect your device's advertising identifier, we do not use these events for advertising, and we do not share them with data brokers.

MusicDen does not use your microphone or your location.

i. Data collected through TranslateDen

TranslateDen uses the same account, learning and technical data described above. In addition, when you use TranslateDen we process:

• A guest account: TranslateDen can be used without signing in. We then create an anonymous account tied to your device that stores your languages, saved words and flashcard progress. If you later create an account or sign in, the guest account's data is moved into that account.
• The text you translate: the word, sentence or paragraph you type or paste, the source and target languages, and the translation we return. The text is sent to our servers and AI providers to produce the translation and, when you tap a word, the meaning of that word in its sentence (see Section 1.f).
• Translation and learning languages: the languages you translate between and the languages whose words you save.
• Words you save and your flashcard results: the word, the sentence you found it in, and how you answered when reviewing it.
• Your plan's monthly allowance: how much of your translation and AI allowance you have used, so that we can show the remaining amount and apply the limit of your plan.

Den keyboard: TranslateDen includes an optional keyboard that you can enable in your phone's keyboard settings. When you tap Translate on the keyboard, the text you have selected or typed in the current text field is sent to our servers and translated, and the translation replaces that text. The keyboard sends text only when you tap Translate; it does not record your keystrokes, does not read other text on the screen and does not send anything you type while you are not using it. On iOS, the keyboard needs the "Allow Full Access" permission so that it can connect to our servers; without it the keyboard still types but cannot translate.

Notifications: if you allow notifications, TranslateDen can send you reminders and news about the app. As with MusicDen, a notification is sent to only one of our apps on your phone, so you do not receive the same notification twice.

Usage analytics: like the App and MusicDen, TranslateDen sends usage events to Mixpanel and Firebase Analytics, such as which screens you open, how many translations you make and which buttons you tap, together with your account ID, app version, device model and interface language. The events do not contain the text you translate. We do not collect your device's advertising identifier, we do not use these events for advertising, and we do not share them with data brokers.

TranslateDen does not use your microphone, your camera or your location.

2. How We Use Your Information

We may use your information to:

• Provide and operate the App, MusicDen, TranslateDen and the Extension
• Create and manage user accounts
• Provide the Extension's word selection, translation, subtitle, and save-to-vocabulary features
• Sync your account, saved vocabulary, subscription, and progress across the App, MusicDen, TranslateDen and the Extension
• Personalize the language learning experience
• Show progress tracking, learning history, and performance insights
• Deliver stories, exercises, flashcards, and other learning content
• Deliver and personalize educational video excerpt content and associated vocabulary exercises
• Provide MusicDen's song games, leaderboards and song requests
• Provide TranslateDen's translations, word meanings, saved words, flashcards and the Den keyboard
• Send the notifications you have allowed in the App, in MusicDen or in TranslateDen
• Provide AI-powered explanations, analysis, and recommendations
• Verify subscriptions and purchases
• Detect errors, prevent abuse, and improve security
• Respond to support requests
• Improve performance, analytics, and user experience
• Comply with legal obligations

3. How We Share Information

We may share your information only when necessary and only with:

• Hosting and infrastructure providers
• Analytics and crash reporting providers
• Payment and subscription service providers
• AI service providers, to the extent required to deliver relevant features
• Content delivery network providers for video content delivery
• Public authorities or legal bodies, when required by law

We do not sell your personal data.

4. Third-Party Services We Use

The Services may use third-party providers to support authentication, analytics, subscriptions, AI features, crash reporting, hosting, and infrastructure. These providers may process personal data in accordance with their own privacy policies.

Services we use may include:

• Firebase (authentication and analytics — App, MusicDen and TranslateDen)
• RevenueCat (subscriptions — App, MusicDen and TranslateDen)
• OneSignal (push notifications — App, MusicDen and TranslateDen)
• OpenAI (AI language features and translation)
• Sentry (error reporting)
• DigitalOcean (hosting)
• Mixpanel (analytics)
• YouTube / Google LLC
• Musixmatch (song lyrics — App and MusicDen)
• Cloudflare

The App and MusicDen use YouTube's iframe embed feature to display video content, including the music videos in MusicDen. When you interact with embedded YouTube videos, Google LLC may collect data (such as your IP address, device information, and interaction data) in accordance with Google's Privacy Policy. Vocabden does not control how Google collects or uses this data. By using features that include YouTube videos, you acknowledge and agree to Google's data practices.

The App and MusicDen use Musixmatch to provide song lyrics. Lyrics are licensed to us by Musixmatch and remain the property of their respective rights holders. Musixmatch receives the information needed to retrieve lyrics for a song (such as the song title and artist), not your personal account data, and its handling of data is governed by Musixmatch's Privacy Policy. Vocabden does not control how Musixmatch collects or uses data.

The App uses Cloudflare's content delivery network to serve educational video content. When you view video excerpts within the App, Cloudflare may process technical data (such as your IP address and request metadata) in accordance with Cloudflare's Privacy Policy. Vocabden does not control how Cloudflare collects or uses this data.

5. Browser Extension Permissions

The Vocabden browser extension requests only the permissions it needs to provide its features:

• Storage — to keep you signed in and remember your settings and saved words locally in your browser.
• Active tab and host access — to read the word or subtitle text you select on the page you are viewing so it can be analyzed or translated.
• Context menus — to add the "Analyze with Vocabden" option to your right-click menu.
• Identity — to let you sign in securely with your Google account.
• Offscreen — to run authentication and AI connection tasks in the background.

We do not use these permissions to track your browsing or to collect data from pages where you are not actively using the Extension.

6. Google API Limited Use

Vocabden's use and transfer of information received from Google APIs to any other app will adhere to the Chrome Web Store User Data Policy, including the Limited Use requirements. Information obtained through the Extension is used solely to provide and improve the user-facing features of the Services, is not transferred to third parties except as needed to provide those features or as required by law, and is never sold or used for advertising.

7. International Data Transfers

Some of the service providers we use may process data on servers located outside your country. When this happens, we take reasonable steps to ensure that data is protected in accordance with applicable laws and appropriate safeguards.

8. Data Retention

We retain personal data:

• for as long as necessary to provide the Services,
• for the period required by legal obligations,
• and for legitimate business purposes such as security, recordkeeping, dispute resolution, and fraud prevention.

Den practice: practice and attempt results are kept until you delete the practice or your account. The part of your last corrected sentence (up to 200 characters) is deleted automatically if you do not use that practice for 180 days; the corrected version and the reason remain. Deleting your account deletes all of it immediately.

When data is no longer needed, we delete, anonymize, or securely dispose of it where appropriate.

9. Data Security

We use reasonable technical and organizational measures to protect personal data against unauthorized access, loss, misuse, or disclosure. However, no internet transmission or electronic storage system can be guaranteed to be 100% secure.

10. Children's Privacy

The Services are not intended for children under the age required by applicable law without appropriate parental or guardian involvement.

If we become aware that we have collected personal data from a child in violation of applicable law, we will take appropriate steps to delete that information.

11. Your Rights

Depending on your location and applicable law, you may have the right to:

• request access to your personal data,
• request correction of inaccurate or incomplete data,
• request deletion of your data,
• object to or restrict certain processing,
• request portability of your data,
• and exercise other legal rights available to you.

To submit a privacy-related request, contact us at:
[email protected]

12. Account Deletion

You can delete your account from the account page in the App, in MusicDen or in TranslateDen. You may also request deletion of your account and associated personal data by contacting us at:
[email protected]

Because the App, MusicDen, TranslateDen and the Extension share one account, deleting it removes your account, saved words, learning progress, translation history, game results and leaderboard entries from all four products. Deleting your account does not cancel a subscription: cancel it in the App Store or Google Play subscription settings of the store where you bought it.

We may retain certain information where necessary to comply with legal obligations, resolve disputes, enforce agreements, or maintain security and fraud prevention measures.

13. Changes to This Privacy Policy

We may update this Privacy Policy from time to time. When we do, we will revise the "Last Updated" date above. Material changes may be communicated through the App, MusicDen, TranslateDen, the Extension, our website, or other appropriate channels.

14. Contact Us

If you have any questions about this Privacy Policy, please contact us: