Vocabulary Highlighter — Learn Words While You Read

Highlight unknown English words on any website. Flashcards, spaced repetition, word frequency. No account needed. 100% private.

Learn English vocabulary by reading websites you already love — Reddit, Medium, news, documentation, anything. HOW IT WORKS Open any webpage → click "Activate" → every word gets color-coded. Green = you know it. Red = you don't. Click an unknown word, press Enter — it's added to your dictionary. The extension remembers. Over time, you see fewer red words. That's your progress. FLASHCARDS WITH SPACED REPETITION (NEW in 0.2.0) Unknown words you encounter while reading automatically become flashcards. Practice them with a 3-button rating system (Don't know / Kinda know / Know it). The built-in spaced repetition algorithm schedules reviews at optimal intervals so you remember words long-term. WORD FREQUENCY TRACKING See which unknown words appear most often across everything you read. Filter by time period: last 7 days, 30 days, 90 days, or all time. Focus on high-frequency words first — they give you the biggest reading comprehension boost. QUICK SETUP QUIZ Mark 1,500 common English words you already know in batches of 150. Takes a few minutes. After that, the extension only highlights words you actually need to learn. CLICK-TO-TRANSLATE Click any word on the Learn Words page or inside flashcards to instantly see its definition and part of speech. No need to open a separate dictionary. FEATURES - Color-coded word highlighting on any website - Flashcards with spaced repetition (SM-2 algorithm) - Top unknown words ranked by frequency - Inline definitions from free dictionary API - Quick setup quiz (1,500 common words) - Customizable highlight colors and opacity - Import/export word lists (CSV) - Reading streaks and daily stats - Cross-device dictionary sync via Chrome PRIVACY No account. No cloud servers. No tracking. Your dictionary syncs through your Chrome profile — only you can see it. All processing happens in your browser. WHO THIS IS FOR English learners (intermediate+) who want to build vocabulary from real content instead of textbook word lists. Works best when you read every day — articles, Reddit threads, documentation, blogs. WHAT'S NEW IN 0.2.0 - Flashcards with spaced repetition - Click-to-translate on Learn Words page - Time period filters (7d / 30d / 90d / all time) - Redesigned popup with compact stats - Quick setup quiz expanded to 1,500 words