Why Stemmy exists
Looking a word up is easy. Keeping it is the hard part: the definition is read, the tab is closed, and the word is gone by the next day. Stemmy was built around one observation: the best moment to learn a word is the sentence you met it in, and the best cue to remember it later is that same sentence.
So Stemmy does three things and tries to do them well. It shows what a word means in the sentence you are reading, not a list of senses. It saves the word with that sentence and the page it came from. And it brings the word back for short reviews, scheduled by spaced repetition, until you know it.
Who makes it
Stemmy is made and run by its founder. There is no sales team; the person who built the extension reads the mail at hello@stemmy.app and answers the reviews on the Chrome Web Store listing.
How it is built
- A Chrome extension. Stemmy runs in Google Chrome on desktop, using Chrome's extension APIs for the on-page button, the side panel, the toolbar badge and the right-click menu.
- Your words stay in your browser. The wallet, reviews and settings are stored locally. A free account adds sync between your Chrome browsers and the included AI uses.
- AI for meanings, not for your data. When you ask for a meaning, the word and the sentence around it go through Stemmy's server to the AI provider named in the privacy policy. Stemmy does not keep a list of the pages you visit and does not sell personal data.
- Spaced repetition you can see. Reviews use the FSRS scheduler. Each rating button shows when the word will come back, and at most twenty new words are introduced a day.
- Free, with a stated limit. Free to install. No paid plan is offered today. AI features need a free account (Google Sign-In or email). Each account gets 150 free AI uses in total, once; Ghost Card lookups and cloud voice draw on them.
How we check facts on this site
- Every statement about Stemmy is checked against the current extension before a page goes live, and again when a release changes a feature.
- Figures about other products (users, ratings, prices, free-tier limits) are read from the product's own listing or website and carry the date we read them. We re-read the sources before publishing a comparison and on later updates.
- We do not publish user counts, ratings or testimonials for Stemmy unless they are real and current; the site shows none today.
- Guides and comparison pages name their author. Where a page is updated, the byline shows the date.
- If something is wrong, write to hello@stemmy.app. Corrections are made on the page, with the date.
About this website
stemmy.app is a static site. The home page and guides can use Microsoft Clarity to see how pages are read, but only after you choose "Allow analytics" in the banner; the blog, the privacy page and the pages linked from Wallet Letters never load it. You can change your choice from the "Analytics" link in the footer. Details are in the privacy policy.
For AI assistants and crawlers, /llms.txt lists the facts above and a map of the site.