Privacy Policy

1. Controller

Claude Flaig, Lucerne, Switzerland · mail@zen-tr.com

2. Website

No marketing tracking or marketing cookies. The website does not use advertising profiles, tracking pixels or marketing cookies.

Anonymous usage statistics: To understand which content is read and where visitors come from, the website collects self-hosted, anonymous statistics – without cookies and without storing anything in your browser. We record the page viewed, the sections that came into view, scroll depth and time on page, clicks on the TestFlight button and other controls, the referring website, UTM parameters, device type, browser, operating system, language and country. IP addresses are not stored; the IP address, browser identifier and a secret that changes daily are only used to derive a non-reversible daily value that can no longer be linked to a visit after 24 hours. The data is stored on Cloudflare infrastructure, individual records are deleted after 120 days, and nothing is shared with third parties. The legal basis is our legitimate interest in improving the website.

Cloudflare Web Analytics: We also use Cloudflare Web Analytics to measure page views and loading performance (Core Web Vitals). The page loads a small script from Cloudflare that works without cookies, stores nothing in your browser and does not build visitor profiles. It transmits the page viewed, the referring website, browser, operating system, device type, country and performance measurements. Cloudflare processes this data on our behalf. The legal basis is our legitimate interest in a fast and reliable website.

Hosting: The website is delivered through Cloudflare Pages (Cloudflare Inc., 101 Townsend Street, San Francisco, CA, USA). Cloudflare processes technically necessary connection data such as IP address, time, requested resource and user agent to deliver the website securely.

TestFlight: The button on this website opens Apple's public TestFlight invitation link directly. We do not collect TestFlight signups on this website, store email addresses for that purpose, or send invitations manually.

3. General app data

Your library, favorites, queue, inbox, settings, playback positions and history are generally stored on your device. If you enable optional iCloud sync, this data is synchronized between your devices through your private iCloud/CloudKit account. Apple processes that data under its own privacy terms. We do not operate a user-account or library server and do not have direct access to this data.

Apple Music: If you connect Apple Music, zentr loads catalog data such as artists, albums, titles and artwork through Apple's MusicKit and plays content through Apple Music. These requests go directly to Apple and are subject to Apple's privacy policy. We do not receive any data from your Apple Account.

Podcasts: zentr loads feeds, episodes and artwork directly from the servers of the respective podcast providers. Like with any podcast player, they receive technically necessary connection data such as your IP address, the time and the app identifier. For podcast search, your search term is sent to Apple's iTunes Search API. Credentials for private feeds are only sent to the respective provider.

Your own audio files: Files you import from the Files app or your iCloud Drive folder stay on your device or in your iCloud Drive. We do not receive them.

Sleep data from Apple Health: Only if you explicitly allow it, zentr reads sleep analysis from Apple Health – read-only and no other health data. The data is evaluated only on your device to suggest rewinding to the moment you fell asleep after a night with the sleep timer ("Sleep Rewind"), to show your nights with their sleep stages and what played in zentr under Settings → Sleep ("Your nights"), and to show in your statistics how many minutes it takes you to fall asleep with each kind of content ("Falling asleep"). For this, your sleep data is linked to your listening time only while it is displayed and is not stored. The data is not sent to us or third parties, not stored in iCloud and not included in error reports. You can revoke access at any time in the Health app and turn Sleep Rewind off in the settings.

Purchases and subscriptions: You buy subscriptions and Lifetime through the App Store. Apple handles payment and billing; we receive neither payment data nor your Apple ID. The app checks on your device via Apple's StoreKit whether a subscription or purchase exists. The free trial week is an introductory offer in the App Store.

Notifications: Alerts about new episodes, albums and videos, as well as the reminder before the trial week ends, are created locally on your device. We do not operate our own push server for them.

Diagnostic export: In the settings you can export a diagnostic log and send it to us, for example by email, when you report a problem. It can contain titles of content you played, names of sources, and the times of the sleep timer and of falling asleep. The log only leaves your device if you share it yourself or send it along with feedback (see the next paragraph).

Feedback from the app: Under Settings → About → "Send Feedback" you can send us a message. The app transmits your message, the type you chose (bug, idea, other), an email address only if you enter one, plus the app version, build, operating system and version, device model, language/region and whether the app comes from TestFlight. Optional diagnostic log: If you leave the diagnostic log toggle on when sending, a technical log of app events (e.g. playback, sync, errors) is sent along. It contains no personal identifiers such as your name, email address or Apple ID, but can contain titles of content you played, names of sources, and the times of the sleep timer and of falling asleep. If you turn the toggle off, no log is transmitted. Feedback and logs are stored on Cloudflare's infrastructure, which also runs this website, read only by us and deleted once we no longer need them, or immediately on request by email to mail@zen-tr.com. So we can reply faster, an AI service from Anthropic summarises the message and the device details listed above (without your email address and without the diagnostic log) and drafts a reply; Anthropic does not use this data for training. We read and check every reply ourselves before it goes out. If you entered an email address, our reply is sent through the email service Resend. Your IP address is not stored with the feedback; to prevent abuse, only a shortened value that cannot be reversed is derived from it, and it expires after 20 minutes. The legal basis is your request and our legitimate interest in fixing problems (Art. 6 para. 1 lit. b and f GDPR).

Anonymous app usage statistics: To see which features are used and where the app needs work, zentr sends anonymous usage events to TelemetryDeck (TelemetryDeck GmbH, Germany; processing in the EU). We record which content type was played on a given day (audio drama, music, podcast, YouTube or your own files), that a sleep timer was set (kind and duration), that the subscription offer (paywall) was shown, that playback was blocked without a subscription (with the content type), that onboarding was completed, and once a day your chosen appearance settings (colors, player style, card style, font, app icon). The SDK also sends standard technical details such as device model, iOS and app version, and language/region. We do not send titles or names of what you play, search terms, accounts, purchases, or health or sleep data. Only in TestFlight beta versions does the app additionally send the name of audio drama series, artists and podcasts played (at most once per series per day, with the content type; taken from the public Apple Music catalog or the podcast feed). This helps us improve the app during the free beta. Episode or album titles, anything from YouTube (neither channels nor videos), your own files and your own playlists from your Apple Music library are never sent, not even there. The App Store version sends no such names. The user identifier is derived from your device's app identifier (vendor ID): it is salted and hashed on your device and salted and hashed again by TelemetryDeck. It cannot be traced back to you, is not linked with other data and is not used for tracking. TelemetryDeck does not store IP addresses. TelemetryDeck does not specify a fixed deletion period; according to TelemetryDeck, the anonymous events are expected to be deleted after seven to ten years. The legal basis is our legitimate interest in improving the app (Art. 6(1)(f) GDPR; in Switzerland, the revFADP). As with crash reports, we do not ask for consent for accessing your device within the meaning of Section 25 TDDDG; instead, you can turn this off at any time under Settings → Legal → "Send usage statistics". When it is off, nothing is sent. In TestFlight versions, the series, artists and podcasts played can allow conclusions about interests even though the data is anonymous; this is another reason you can turn the statistics off at any time.

4. YouTube API Services: data accessed and stored

zentr uses the YouTube Data API, public YouTube RSS feeds and the official YouTube IFrame Player for playback.

zentr may access, display and locally store the following publicly available YouTube API Data:

• channel ID, channel name, handle or custom URL, channel description and channel image;
• uploads playlist ID and, where returned by the API, public channel statistics;
• video ID, title, description, channel association, publication date, thumbnails and video duration supplied by YouTube;
• public upload entries and video IDs from YouTube RSS feeds.

No Google sign-in: zentr currently does not connect a Google or YouTube account, does not use OAuth authorization, and does not access private YouTube data, subscriptions, comments, likes, YouTube watch history or contact information from a Google account.

5. How YouTube data is used and processed

The retrieved data is used only to search public channels, display selected channels in your local library, show public uploads, open videos through the official YouTube player or YouTube app, and organize content you select in the zentr queue or inbox.

zentr product data: Favorites, queue/inbox placement, personal playback positions and manually selected status information are local zentr features and are not supplied by YouTube. They must not be understood as YouTube metrics.

Local caching: Search results are cached briefly in memory. Public channel and video metadata and thumbnails may be stored on the device so that the library and inbox can work without downloading everything again whenever they are opened.

6. Refresh, retention and deletion of YouTube API Data

Stored YouTube API Data is regularly checked against current data supplied by YouTube. Stored API Data is refreshed or deleted no later than every 30 calendar days. Content that is no longer available, has been deleted or has become private is removed from local presentation and API-data storage when that change is detected during refresh.

If you unfollow a YouTube channel, its stored YouTube channel and video metadata is deleted unless it is still needed for an item you explicitly retained in your queue, inbox or history.

Deletion by you: Through Settings → Reset Data, you can immediately delete all content and YouTube API Data stored by zentr (library, queue, inbox, history, progress, and all channel and video data); pure app preferences such as language or theme are retained. If iCloud synchronization is enabled, the deletion is also propagated to records synchronized by zentr in your private iCloud/CloudKit account. Uninstalling the app removes local app data; to reliably delete previously synchronized iCloud data, use “Reset Data” before uninstalling.

We do not operate our own user or data storage service for your app data and cannot access data on your device or in your private iCloud/CloudKit account. Remote deletion by us is therefore not technically possible. If you have questions or problems deleting data, contact mail@zen-tr.com; we will assist you as soon as possible and within seven calendar days. Deleting data in zentr does not delete or modify data held by YouTube or Google.

7. Sharing and external recipients

• Google/YouTube: Search, retrieval and playback requests are sent directly to Google/YouTube services. They may process your IP address, device and connection data, and the requested channel or video ID.
• Apple iCloud/CloudKit: only if you enable optional synchronization; locally stored library and playback data may then be synchronized between your devices.
• Sentry: for error, crash and app-hang diagnostics (Functional Software Inc., USA; data is stored in the EU, in Germany). The app sends the app version, device model, operating system, error and stack data, a technical log of the last steps before the error (playback and navigation events with internal identifiers, without titles, search terms or web addresses), and a random, anonymous installation ID created on your device. Automatic screenshots as well as network and user-interaction tracking are disabled. Sentry deletes error reports after 90 days at the latest. In addition, the app sends anonymous usage figures about the YouTube interface once a day: how many YouTube Data API requests were made that day, broken down by type and purpose (e.g. channel page, search, refresh), the type of your access (free, trial, subscription or lifetime) and whether only YouTube was used on free access – without channel or video IDs, titles or search terms. This lets us check whether the daily quota assigned by Google is sufficient for all users. You can turn this off at any time under Settings → Legal → "Send crash reports".
• TelemetryDeck: anonymous app usage statistics (TelemetryDeck GmbH, Germany; processing in the EU), see "Anonymous app usage statistics" above. You can turn them off at any time under Settings → Legal → "Send usage statistics".
• Cloudflare: storage of feedback and the optional diagnostic log you send from the app (Cloudflare Inc., USA), see "Feedback from the app" above.
• Anthropic: summary and reply draft for feedback from the app, without email address and diagnostic log (Anthropic PBC, USA).
• Resend: sending our replies to feedback if you entered an email address (Resend Inc., USA).
• Apple: for Apple Music (MusicKit), podcast search (iTunes Search API), purchases and subscriptions (App Store) and the optional iCloud sync, each under Apple's privacy policy.
• Podcast providers: feeds, episodes and artwork you follow or open are loaded directly from their servers.

We do not sell YouTube API Data or personal data, use it for advertising or cross-user profiling, or share it with other internal or external parties except as described above or where required by law.

8. Google and YouTube terms

Use of YouTube features is also subject to the YouTube Terms of Service and the Google Privacy Policy.

9. Your rights

For contact requests, you may request access, correction, deletion, restriction and, where applicable, portability. For library, playback and YouTube API Data stored locally in the app or in your private iCloud/CloudKit account, there is no deletion request to make to us: we do not store this data on our own servers, cannot access it, and therefore cannot delete it remotely. You delete this data directly through the existing “Settings → Reset Data” function.

Legal bases (where the GDPR applies): Processing for the app's features is necessary to provide the service you use (Art. 6(1)(b) GDPR); error and crash diagnostics are based on our legitimate interest in a stable app (Art. 6(1)(f) GDPR), and you can object at any time; reading sleep data from Apple Health happens only with your explicit consent (Art. 9(2)(a) GDPR), which you can withdraw at any time.

You may also lodge a complaint with the Swiss Federal Data Protection and Information Commissioner (FDPIC) or another competent authority. Send requests concerning data we actually process to mail@zen-tr.com.

10. Changes

We update this policy when our processing, app features or legal requirements change. The current version remains permanently available on this page.