The
Cognitive
Overlay
for
the
Web
Highlight any word on any webpage to unlock instant AI-powered definitions, etymology, and examples. Build a living vocabulary wallet that grows with your curiosity.
Every Word Becomes
a Learning Moment
Stemmy transforms your everyday browsing into an immersive vocabulary laboratory. No context-switching. No flashcard apps. Just learn as you read.
Ghost Card
Select any word and summon a beautiful floating definition card — pronunciation, etymology, examples, and part of speech, all in one elegant overlay.
⌘ Ctrl + ESide Panel
A full immersive learning workspace that slides in from the side — review flashcards, read AI-generated stories built from your words, and track your progress.
✦ AI StoriesVocabulary Wallet
Every word you learn is stored in a personal wallet — searchable, sortable, and organized by mastery level. Watch your collection grow over time.
∞ Unlimited WordsSpaced Repetition
Powered by the SM-2 algorithm — the same science behind the most effective memory systems. Stemmy knows exactly when to review each word for maximum retention.
✦ SM-2 AlgorithmWord Immersion
Hit the brain button and watch your saved words come alive on any webpage. Stemmy's X-Ray scans the page and highlights every vocabulary word you're learning — hover any highlight to instantly review its definition without leaving the page.
⚡ One-Click X-RayStart Building Your
Vocabulary Today
Transform your everyday browsing into a vocabulary-building experience. Free forever, no sign-up required.
No sign-up required · Works on all websites · Open source