Chrome Extension · Free

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.

Add to Chrome — Free See It In Action
500+ Active Users
12K+ Words Learned
4.9★ User Rating
Stemmy Ghost Card overlay on a webpage
🔮 Ghost Card: Ctrl+E
🧠 SM-2 Spaced Repetition
✨ AI-Powered by Mistral
Capabilities

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 + E
📚

Side 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 Stories
💎

Vocabulary 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 Words
🧠

Spaced 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 Algorithm
🔬

Word 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-Ray
View All Features

Start Building Your
Vocabulary Today

Join hundreds of curious minds who are transforming their browsing into a learning experience. Free forever.

Add to Chrome — Free Explore Features

No sign-up required · Works on all websites · Open source