Langsist turns subtitles from YouTube, TED and Coursera into contextual vocabulary lessons, spaced-repetition practice and real AnkiDroid decks — without leaving the video.
Works where you already learn
One calm panel follows the subtitles in real time. Every word becomes a lesson, every save becomes a card, and every card comes back when you're about to forget it.
Previous, current and next lines in one card. Click any word or Ctrl/Cmd-click a phrase to dig in.
The definition coach gives the meaning in this sentence — plus why it fits, CEFR level, frequency, register and examples.
Words group by video. Saved words stay highlighted in later captions, scoped strictly to that video.
A finite, AnkiDroid-style session builds long-term memory. Dashboard insights show mastery, streak and accuracy.
Generate a genuine .apkg and import it into AnkiDroid on your
phone — text, context and metadata included.
A focused toolkit that respects your attention — professional, calm and readable in light and dark.
Meaning in context with a short teaching rationale, CEFR level, frequency, usefulness, register, synonyms, opposites and an example. Depth adapts to your learner level, and the target word is highlighted in the quoting sentence.
Mastery donut, due today, streak, recall accuracy with week-over-week momentum, a 7-day forecast and CEFR coverage — all derived from your real reviews.
A genuine zipped SQLite .apkg, built on your device. Front masks
half the target word with _ blanks; the back shows the full entry.
AnkiDroid-style cards. "Again" requeues within the session but can never loop forever — sessions always end.
Collections keyed to each video, per-item and per-collection menus, target-word highlighting and a one-click jump back to the checkpoint.
Learner level, native language, dark/light theme, colour palettes, transparency and a fully draggable, resizable panel.
Most tools tell you what a word can mean. Langsist explains what it means here — and why the other meanings don't fit this sentence.
Langsist schedules reviews with an SM-2 style algorithm and shows exactly how your memory is holding up — then hands the deck to AnkiDroid for review anywhere.
.apkg in one clickDownloaded a lecture, a documentary or a course you own? Open Langsist's built-in player, load the video with its subtitles, and every feature works exactly as it does on a website — no internet required.
.mp4, .webm or .mkv fileLangsist keeps your learning data on your device by default. When you sign in, your library, study schedule, review history and settings are backed up to your account on our server so they stay in sync across devices — and cloud sync can be turned off at any time. We never show ads and never sell your data.
Saved words, review history and settings live in
chrome.storage.local. When cloud sync is on, they're also backed up to
your Langsist account so they can be restored on other devices. Auth tokens are
never uploaded, and they're stripped from backups.
Beyond account sync, network calls happen only when you ask: an AI definition, a dictionary fallback, or a Google sign-in. Nothing is sent to advertisers or data brokers.
Generating an .apkg happens entirely on your device. Nothing is
uploaded.
Page text is escaped, model output is sanitized, backups are validated, and no code is loaded from a CDN.
Every core feature — live captions, the library, spaced repetition and AnkiDroid export — is available on the free tier.
$0forever
.apkg export$11.99/ 3 months
or $4.99 / month · cancel anytime
A free account is required to get started. Upgrade to Pro for higher AI limits and cloud sync across devices.
YouTube (including SPA navigation), TED & TEDx and Coursera. You can also study your own local video files in the built-in local video player.
TED, Coursera and the local video player use exact text tracks. YouTube captions are read from the rendered DOM, so timing is approximate and subtitle step-navigation is disabled when reliable cues aren't available.
You need a free Langsist account — sign in to get started. You don't need your own API key: AI definitions run through Langsist, with a public-dictionary fallback when a definition isn't available.
Yes. Langsist generates a genuine zipped SQLite .apkg — a real
collection.anki2 — that imports directly into AnkiDroid.
Locally, in your browser. If you sign in and keep cloud sync on, your library, study schedule and settings are also backed up to your Langsist account so they can be restored on any device. We additionally collect limited product analytics to improve the extension. See the privacy section for details.
Install Langsist, open a supported video, and turn the next subtitle into a word you'll remember.
extension/dist/ folder (or unzip the release)chrome://extensions and enable Developer modeextension/dist/