Last updated: 2026-09-30
Twinline is a browser extension, built and maintained by an independent developer, that shows dual-language subtitles on YouTube to help you learn languages. I do not collect, sell, or share your personal information.
| Data | Purpose | Where it is kept | Does it leave your device |
|---|---|---|---|
| Captions of the YouTube video you are watching | Showing dual subtitles | In memory on the current page only | No. Captions are fetched directly from YouTube and never pass through any server of mine |
| A word you click to look up | Looking up its meaning | Not stored | Yes. The word alone is sent to the third-party Free Dictionary API |
| Your word list (words, definitions, sentences, translations, video links and timestamps) | Helping you review | Locally in your browser (chrome.storage.local) |
No, unless you export it as a CSV or Anki file yourself |
| Settings (on/off, target language, font size, etc.) | Remembering your preferences | Browser sync storage (chrome.storage.sync) |
If Chrome Sync is on, Chrome syncs them to your Google account; Google handles that |
Click "Clear" in the extension popup to delete your word list. Uninstalling the extension deletes everything it stored locally.
Twinline is an individual project. If you have any questions about this policy or your data, please contact me at the developer email address listed on Twinline's Chrome Web Store page.
If this policy changes, I will update this page and the "Last updated" date above.