Duosub
Last updated 10 October 2026
Duosub shows dual subtitles. Translation runs on your computer first; the cloud is only a fallback.
Stays in your browser
Subtitles are fetched from YouTube or Netflix by your browser, as the player itself does.
Saved words, review history, stats and settings stay in your browser.
Chrome’s built-in on-device translator is used whenever it is available.
Sent to our server
When on-device translation isn’t available, or you ask for a word card or line explanation: the subtitle lines or word and sentence, with the language pair. Answers are cached and shared across users without recording who asked.
Daily counts for the free and Pro allowances.
If you opt in to “Help improve”: whether subtitles loaded on each site, which feeds the public status page.
Like every extension we make: your install id, your licence if you have one, usage counts for plan limits, and optional “Help improve” data if you turn it on. See the main privacy policy.
Other services
Anthropic (Claude): Cloud translation, word cards and line explanations (subtitle text only).
Your choices
Uninstalling removes everything the extension stored in your browser. To have the data on our server deleted, email us.
We never sell your data or use it for advertising. Duosub follows the Chrome Web Store User Data Policy, including its Limited Use requirements.