Privacy Policy, The Fluent Immigrant browser extension

Effective 26 August 2026. Applies to the "The Fluent Immigrant" extension for Chrome, Edge and Firefox. The web app at app.thefluentimmigrant.com is covered by the general policy at https://thefluentimmigrant.com/privacy. This policy is also published at https://app.thefluentimmigrant.com/extension/privacy

WHAT THE EXTENSION DOES

The extension has a single purpose: it makes the subtitles of videos on youtube.com, netflix.com and Prime Video (primevideo.com, and amazon.com only under /gp/video) clickable, so an English learner can look up a word, hear it, and mark it as Learning / Known / Mastered in their Fluent Immigrant vocabulary. It runs only on those sites and on app.thefluentimmigrant.com/extension/connect, the page that links it to your account.

DATA THE EXTENSION HANDLES

• Your account connection token. Why: to act on your behalf (save words to your vocabulary). It is created when you press "Connect" in the app. Where: stored on your device (extension storage) and sent only to our API with each request. You can revoke it any time from the app (Settings, Browser extension); a revoked token stops working immediately.
• Subtitle text of the video you are watching. Why: to translate the current line into your language and to colour words by your vocabulary state. Where: for the line translation, each subtitle line is sent from your browser to Google Translate (translate.googleapis.com) with only the text and the language pair; lines Google could not translate go to our API and from there to Google Gemini. Word lookups and translated lines are cached on our servers so the same text is not processed twice, not tied to your account; that cache is deleted after 365 days.
• Words you click or mark. Why: to show the explanation and to save the word to your vocabulary. Where: sent to our API. The word and its state become part of your vocabulary in your account, exactly as if you had marked it in the app.
• Your extension settings (translation on/off, font size, etc.). Why: so the overlay behaves the way you set it. Where: stored on your device only.

WHAT THE EXTENSION DOES NOT DO

• It does not collect your browsing history, the pages you visit, or which videos you watch. It only reads the caption text on a video page you already opened, and only while the overlay is enabled. On some sites it turns the player's captions on and selects the English track for you, so the overlay has text to work with.
• It does not read your Netflix, YouTube or Amazon account, cookies, or credentials.
• It does not use analytics, advertising or tracking SDKs, and it does not sell or share data with data brokers.
• It does not run on any site other than the ones listed above.

WHO RECEIVES DATA

Only The Fluent Immigrant's own API (api.thefluentimmigrant.com, hosted on Render) and, for the parts of a request that need them, our processors: Google Translate (sentence translation, sent directly from your browser), Google Gemini (sentence translation for lines Google Translate could not handle, and word explanations, cached and not tied to you) and OpenAI (text-to-speech audio for a word you ask to hear). They receive the text needed for that one request and nothing about your identity.

RETENTION AND DELETION

Words and states you save live in your account until you change or delete them, or delete your account (Settings, Account), which removes them together with every extension token. Disconnecting the extension in the app revokes its token; uninstalling the extension deletes everything it stored on your device.

PERMISSIONS, IN PLAIN WORDS

• storage: keep your settings and connection token on your device.
• scripting: start the extension's own script on a video tab that was already open before the extension was installed or updated, so you do not have to refresh it. It runs only the code shipped in the extension, never anything downloaded, and it never reloads a page.
• Access to www.youtube.com, www.netflix.com, .primevideo.com and www.amazon.com/gp/video/: read the caption text and draw the clickable overlay on the video.
• Access to app.thefluentimmigrant.com and api.thefluentimmigrant.com: link the extension to your account and talk to our API.

CHANGES

If this policy changes in a way that matters, the extension's store listing and this page will say so, with the new effective date at the top.

CONTACT

Questions or requests about your data: support@thefluentimmigrant.com

Notes to Reviewer box:

BUILD (source zip attached)
Node 22, npm 10. Unzip the source, then in that folder:
npm install
node build.mjs
Output: dist/firefox. It is byte-identical to the uploaded fli-extension-firefox-0.1.0.zip (verified with diff -r before upload). The only build dependency is esbuild, pinned to the exact version in package.json. build.mjs is plain esbuild bundling of src/, no minification tricks, no remote code.

HOW TO TEST
1. Create a free account at https://app.thefluentimmigrant.com (sign-in is passwordless: you enter your e-mail and receive a 6-digit code, so there is no password to give you; any e-mail address works and the first 3 days are full access with no card). If you would rather have a pre-made account, e-mail support@thefluentimmigrant.com and we will extend one for you within a day.
2. Install the add-on, click its toolbar icon, press "Connect account". The app opens https://app.thefluentimmigrant.com/extension/connect and hands the extension a token.
3. Open any YouTube video with English captions, for example https://www.youtube.com/watch?v=arj7oStGLkU (TED talk, manual English captions). The add-on turns captions on by itself. Words in the subtitle become clickable; click one for the card, hover it for the short senses card. A button after YouTube's fullscreen button opens the settings menu.
4. Netflix and Prime Video need a subscription to those services; the behaviour is the same (clickable subtitle line on the player).

PERMISSIONS
- storage: settings + the connection token.
- scripting: injects the extension's OWN bundled content script into a video tab that was already open before install/update, so the user does not have to refresh. Nothing downloaded or evaluated, never navigates or reloads a page.
- host permissions are limited to the four video sites (amazon.com only under /gp/video/*) and our own two domains.
- content scripts with world: "MAIN" (yt-hook, nf-hook, pv-hook) only observe the caption files the site's own player downloads (XHR/fetch wrappers) and forward the text to the isolated script via a DOM CustomEvent. They do not modify site requests.
- Third-party requests from the browser: subtitle lines go to translate.googleapis.com for the line translation (text + language pair only). Disclosed in the privacy policy.

Data collection declared in the manifest (authenticationInfo, websiteContent) matches the privacy policy.