Privacy Policy

1. Information we process

Captions and translations. When you start interpretation, the extension reads available captions and timing information for the current YouTube video, groups captions into translation segments and processes the resulting translations. Captions may contain names or other personal information. Requests sent to our translation proxy contain caption text, source and target languages, and the streaming option—not complete video files, video audio or browser account credentials.

Video information and preferences. On your device, the extension uses the current video identifier, playback position, speaker labels, voice mappings and cached translations to synchronize playback and avoid repeated requests. Daily usage time is stored in Chrome local storage. Voice preferences and prompt counters use Chrome sync storage; cross-device synchronization depends on your browser settings.

Network and diagnostic information. Hosting providers process information needed to serve website and translation requests, such as IP addresses, request times and request metadata. The translation proxy uses IP addresses for rate limiting and logs request identifiers, response status, timings and output character counts. Browser-side segmentation diagnostics may contain video identifiers and excerpts of caption text. Review and redact logs before sharing them.

Communications you send us. If you email us, we receive your email address, message and attachments to address your feedback or privacy request. Please provide only the information necessary to resolve your issue.

2. Purposes and grounds for processing

We use this information to provide caption translation and speech playback, synchronize video progress, remember voices, calculate local usage time, reuse cached translations, limit abnormal requests, diagnose service failures and respond to feedback and data requests.

Processing must have a basis required by applicable law, such as providing the service you request, protecting service security or obtaining consent where required. You can stop interpretation or disable the extension to stop subsequent translation requests. This does not withdraw information already sent to providers.

The current extension and proxy do not include features for selling user data, targeted advertising, cross-site behavioral tracking or training our own models on captions. We do not use extension data for purposes unrelated to interpretation. Providers process received content under their applicable agreements and policies; this policy does not guarantee that third parties never retain data or use it for training.

3. Providers and information transfers

• YouTube: Provides the video and captions. Caption retrieval may use your existing YouTube session in the browser; its credentials are not forwarded to the translation service.
• Cloudflare: Hosts the translation proxy, handles caption requests, network connections and necessary operational logs, and provides rate limiting.
• DeepSeek: Receives caption text and translation instructions from the proxy and returns translated text. API data handling is governed by the applicable platform agreement and service arrangements.
• Browser and voice providers: Chrome speech synthesis receives text to be spoken. Online voices may send translations to a speech provider; playback in the browser does not necessarily mean local synthesis. Chrome preference synchronization also depends on your account and sync settings.
• Website hosting: The website is independently deployed in the synclingo.dev operator’s Cloudflare Workers account. It does not use ChatGPT Sites for page delivery or access authentication. Cloudflare may process access logs, necessary cookies and security verification information.

See the Cloudflare Privacy Policy, DeepSeek Open Platform Terms and Google Privacy Policy for provider-specific rules. These references do not replace SyncLingo’s responsibility for its own processing.

4. Storage and retention

Browser caches and preferences. Translation caches, speaker mappings and preferences are stored in browser storage or IndexedDB. The current version has no automatic expiration for these persistent records. Daily usage counters reset for a new date; other caches are not deleted daily. You can manage these records by removing the extension, clearing extension-related data and managing Chrome sync settings. Uninstalling does not delete requests or logs already received by providers.

Translation service. The current proxy code does not write captions or translations to a separate persistent database; content is used during request processing. Hosting platforms retain necessary operational logs according to their configuration. Retention by Cloudflare, DeepSeek, voice and sync services depends on the applicable configuration and agreements. Contact us for details or to request deletion.

Email communications. We retain communications only as needed to address your request, fulfill applicable obligations or maintain necessary records. Do not include unnecessary sensitive information in feedback.

5. Global service and international processing

Providers may process information outside your country or region. Translation requests involve a cloud proxy, model service and potentially online speech services; we do not promise that all data stays on your device or within your region. International processing is subject to applicable notice, consent and safeguard requirements. Contact us for information about locations and service arrangements. Do not use the service to translate confidential content or private information you are not entitled to submit.

6. Permissions, cookies and security

The extension uses storage permission for preferences, caches and usage counters, and tabs permission to communicate with the current video tab. It operates on permitted YouTube pages and the translation endpoint. The current version does not request history, microphone or camera permissions, or include functionality to read unrelated website content.

The website currently has no advertising trackers or separate behavioral analytics scripts added by us. Hosting platforms and YouTube may use their own necessary cookies, sessions or security mechanisms. You can manage these in your browser.

Caption requests use HTTPS. The DeepSeek API key stays on the server and is not distributed in the extension package. Online services and network transmission still carry risks; we cannot guarantee absolute security.

7. Your choices and privacy rights

You can stop interpretation, change voices, manage Chrome sync, disable or uninstall the extension, and clear extension-related browser data. Clearing data may remove caches, usage counts and preferences. The current version does not provide a dedicated button to clear all caches.

Where applicable law provides these rights, you may request access, a copy, correction or deletion of personal information, restrict processing, withdraw consent, object to processing or complain to a supervisory authority. Email rivindong@gmail.com with your request and the information needed to locate relevant records. We will respond within applicable legal deadlines and may need to verify your identity to prevent unauthorized disclosure.

The extension has no separate registered user account, and some data exists only in your browser. We may therefore be unable to locate or delete all local records from our servers. We will assist with provider-held information where feasible and applicable.

8. Minors

Minors should use the service with guardian guidance and comply with local and provider-specific age requirements. Do not submit unnecessary children’s personal information through captions or feedback. Guardians who believe the service has processed a minor’s information inappropriately may contact us to request investigation or deletion.

9. Policy updates

We will update this page and its date when features, providers or information practices change. Material changes should be explained through appropriate website or extension notices, with renewed authorization where required by law. Merely continuing to browse the website is not treated as consent to every new processing activity.