LinguaLens

Vocabulary reinforcement while you read. LinguaLens swaps your studied words inline as you browse.

LinguaLens turns every webpage you read into language practice. Words you've studied get swapped into your target language, in context, while you keep reading the news, watching YouTube, scrolling Wikipedia, or doing your day job. Why it works - Spaced repetition the moment your brain has the context. The flashcard comes from the sentence you're already reading. - Every page becomes a study session. Reading you'd do anyway becomes thousands of low-effort exposures per week. - A real flashcard system underneath. LinguaLens uses FSRS, the modern open-source successor to SM-2, to reschedule cards based on actual recall. What you can do - Import vocabulary from Anki or Skritter, or pick a starter deck and grow it as you read. - Pick from English, Spanish, Mandarin (Simplified or Traditional), Japanese, Korean, Portuguese, French, German, Italian, and more. - Hover any swapped word for the original meaning and a one-tap "I knew it / I forgot" review. - Review due cards on the web app when you have a quiet minute. - YouTube subtitles get the same treatment. - Alt+Shift+L toggles replacements; Alt+Shift+S opens settings. Privacy - LinguaLens only sends short sentence fragments (~200 characters) around words you're studying — never full pages, URLs, or browsing history. - YouTube subtitle text is also captured for inline replacement on YouTube — never the video itself, never your watch history. - Translation is handled server-side by our first-party backend. No third-party data sale. - Read the full policy at https://lingualens.app/privacy Pricing - Free tier: 200 vocabulary cards, all features. - Pro: $5/month or $50/year. Unlimited cards, priority support, and early access to new features. Vocabulary and review state sync to the LinguaLens web app at lingualens.app.