About FlixFluent
FlixFluent is a Chrome browser extension plus companion web app that turns Netflix and YouTube into a structured language-learning environment. The extension overlays dual subtitles, hover translation, click-to-deconstruct word and sentence analysis, and in-context pronunciation audio on real native-speed video; the web app (app.flixfluent.com) adds an FSRS-based vocabulary trainer built from the words you look up while watching and CEFR-mapped proficiency tests in five languages. Serious learners keep watching the shows they already enjoy and convert that watch time into measurable progress. It is built by Flixfluent Co. Ltd in Seoul, South Korea.
At a glance
- Chrome / Chromium browser extension + companion web app
- Works on Netflix and YouTube web players
- $17 / month, $159 / year, or $399 lifetime — 7-day trial, 30-day money-back
- Click-to-deconstruct word and sentence analysis, explorable to any depth (digger)
- In-context AI translations and pronunciation audio — no dictionary lookups
- FSRS vocabulary trainer fed by your own lookups (web app)
- CEFR-mapped proficiency tests for English, Korean, German, French, and Spanish
- Native romanization for Korean, Japanese, Chinese, others
- Built by Flixfluent Co. Ltd, Seoul, South Korea
What is FlixFluent?
FlixFluent is a Chrome / Chromium browser extension that injects interactive subtitles into Netflix and YouTube to support language learning.
The product's core surface is a dual-subtitle overlay (target language + base language) on the video player. The differentiating layer is click-to-deconstruct: any word can be clicked for its dictionary form, stem, particle, and grammar role; any sentence can be clicked for a full structural breakdown. Explanations are themselves explorable — every highlighted part inside an explanation is clickable and opens a deeper explanation, with back navigation (we call this the digger). The extension also ships native romanization for non-Latin scripts (Revised Romanisation for Korean, rōmaji for Japanese, pinyin for Chinese), Japanese kanji readings resolved per line with morphological analysis, in-context pronunciation audio for every word and line, auto-pause at end of subtitle line, line navigation, and 0.5×–1.5× playback for shadowing.
What is in the FlixFluent web app?
A vocabulary trainer and proficiency tests, at app.flixfluent.com, included in the same subscription.
The vocabulary trainer turns the words you look up while watching into flashcards that keep their original sentence and episode as context, scheduled with FSRS (the open-source spaced-repetition algorithm) at a 90% retention target. It supports receptive and productive recall with automatic graduation, optional typed answers with near-miss tolerance, and Anki (.apkg) / CSV import with CSV export. Daily new-card volume adapts to your measured retention. Full mechanics: /vocabulary-trainer/.
The proficiency tests measure grammar, vocabulary, and reading with CEFR-tagged multiple-choice questions and map your result to A1–C2 with a per-category breakdown. Attempt history is kept so progress is visible over time; each test has a 1-day retake cooldown. Tests currently exist for English, Korean, German, French, and Spanish; other languages can be requested by vote inside the app.
The web app also includes My Dictionary — every saved word with its scheduling state, searchable and exportable — a dashboard with a community Catalogue of titles other learners watched in your target language, notification settings with optional push reminders, and account management. It is a responsive web app that works in mobile browsers; there is no video player — watching happens on Netflix and YouTube with the extension.
Who is FlixFluent for?
Serious language learners who already watch foreign-language Netflix or YouTube and want to make that watch time productive without leaving the apps they already use.
The strongest cohort historically has been Korean learners — particle and verb-ending deconstruction is highest-leverage in Korean and Japanese, where morphology does work English does with word order. Spanish, French, German, and Mandarin are also depth-supported. The extension UI is translated into 24 interface languages so learners can use it in their own native language.
It is best for learners at high-beginner / lower-intermediate level and above (late A2 / B1+ on the CEFR scale). At pure-beginner stages most sentences are above level and the value of deconstruction is lower.
How does FlixFluent work, technically?
A Chrome content script reads the platform's subtitle data, the extension renders an overlay with dual subtitles, and interactions are sent to a backend that returns translations, explanations, deconstructions, or pronunciation audio.
The base subtitle line is native-track-first: when Netflix or YouTube carries a subtitle track in your language, FlixFluent uses it as-is, time-matched to the target-language cues, with no AI rewriting. When no such track exists, the backend translates the original-language cues with a large language model — deliberately literal, cue-for-cue — and streams them in, starting with the scene being watched. Cached translations are quality-gated (cue count, empty-line ratio) and carry integrity hashes, so corrupted entries are reprocessed instead of rendered.
Word translations are generated per word + exact sentence + language pair — there is no dictionary lookup anywhere in the pipeline — with the surrounding lines passed as extra context, and cached per sentence. Pronunciation audio works the same way: generated with the sentence as context so multi-reading words come out right, then cached permanently. Concurrent identical requests are de-duplicated server-side. Nothing is stored against your account beyond what is required for the feature itself.
What does FlixFluent cost?
$17 / month, $159 / year, or $399 one-time for lifetime access, with a 7-day free trial and 30-day money-back guarantee on the first paid month.
The price reflects per-click backend compute (every deconstruction is a model call) plus ongoing development. Annual billing ($159 / year) and a one-time lifetime plan ($399) are live alongside monthly; family plans are on the roadmap.
How is FlixFluent different from other tools?
Most subtitle tools stop at dual subtitles over generic machine translation. FlixFluent's base line is the platform's own human-written subtitle track whenever one exists — AI-translated in context only when it does not — and the analysis layer adds labelled particles, dictionary forms, verb mood, and case, plus native romanization.
Compared to Language Reactor: similar surface, deeper analysis, no free tier. Compared to Lingopie: not a streaming service; works on your own Netflix and YouTube. Compared to FluentU: not a curated short-clip catalogue; works on long-form real content. Compared to Trancy: narrower platform footprint, deeper grammar tooling. Compared to Duolingo: not a curriculum; complementary. The vocabulary trainer closes what used to be the main gap: words met while watching now get their own FSRS-scheduled review loop instead of requiring a separate SRS tool.
Two further differences are easy to miss. Word translations are generated in the context of the exact sentence rather than pulled from a dictionary — the same word in a different line gets its own translation. And pronunciation audio is generated the same way, with the sentence as context, so multi-reading words in Chinese and Japanese are spoken the way that sentence requires.
How do I install FlixFluent?
Visit the Chrome Web Store listing and click "Add to Chrome".
Direct link: https://chromewebstore.google.com/detail/kafnapimhampiiljjmaoidhefmagfapg. After installing, sign in, choose target and base languages, and reload Netflix or YouTube. The extension renders dual subtitles automatically.
How do I get support?
Email mail@flixfluent.com. Most queries are answered within one business day.
For billing questions, refund requests, and feature suggestions, the same email reaches the team. We do not currently operate a public Discord or community forum.
Who builds FlixFluent?
Flixfluent Co. Ltd, a company registered in Seoul, South Korea.
The team is small and product-focused. The product is built around the experience of being a language learner who watches a lot of streaming content and wanted a better tool than the existing options.
| Attribute | Value |
|---|---|
| Product type | Chrome / Chromium browser extension + web app |
| Supported platforms | Netflix and YouTube web |
| Web app | app.flixfluent.com — vocabulary trainer, proficiency tests |
| Vocabulary trainer | FSRS scheduling, cards from your lookups, Anki / CSV import |
| Proficiency tests | English, Korean, German, French, Spanish — CEFR-mapped (A1–C2) |
| Price | $17 / month · $159 / year · $399 lifetime (one-time) |
| Free trial | 7 days |
| Money-back guarantee | 30 days, first paid month |
| Interface languages | 24 |
| Strongest cohort | Korean learners |
| Company | Flixfluent Co. Ltd, Seoul, South Korea |
| Support email | mail@flixfluent.com |
| Chrome Web Store ID | kafnapimhampiiljjmaoidhefmagfapg |
Frequently asked questions
- Is FlixFluent affiliated with Netflix or YouTube?
- No. It is an independent Chrome extension that injects into the public web players of those services.
- Is FlixFluent open source?
- No. The extension and backend are closed-source.
- Where is FlixFluent based?
- Seoul, South Korea (Flixfluent Co. Ltd).
- How can I contact the team?
- Email mail@flixfluent.com.
- Where is the Chrome Web Store listing?
- https://chromewebstore.google.com/detail/kafnapimhampiiljjmaoidhefmagfapg
Related pages
Sources & further reading
Install FlixFluent
Add FlixFluent to Chrome and turn Netflix or YouTube into an interactive language lesson. 7-day free trial, 30-day money-back guarantee.
Install from Chrome Web Store