✓ Free · No account · Works offline
Your writing, underlined.
Caret marks spelling, grammar and punctuation mistakes in any text box on any site — e-mail, forms, comment boxes — and fixes them in one click.
Download for Edge & Chrome · 1.5 MB How to install it
Everything runs on your own computer. What you type is never sent anywhere.
Four kinds of mistake
Marked in four colors
Hover any underline for the reason and the fix. Nothing changes until you click it.
Spelling
A 376,000-word dictionary and 4,000 known typos, with suggestions ranked by how common each word really is.
recieved → receivedseperate → separate
Grammar
Confused words, verb forms, agreement, a/an — and the capitals people actually miss.
their is → there ismonday → Monday · DOes → Does
Punctuation
Missing apostrophes, spaces in the wrong place, doubled marks, decades that never needed an apostrophe.
dont → don’tready.Also → ready. Also
Clarity
Wordy stock phrases and things said twice, offered as a suggestion rather than a scolding.
in order to → toeach and every → every
It never rewrites you. Caret suggests a word, or at most a short phrase, and nothing at all changes until you click it. Your voice stays your voice.
Or all at once
Everything it found, in one list
A small count sits in the corner of the box. Click it for the lot, with a Fix all for the unambiguous ones.
About a minute
Installing it
Caret is not in the Edge or Chrome store, so it installs the way developers install extensions. One extra switch — and it is why it can be free and private.
-
Download and unzip it somewhere permanent —
Documents\extensions\is fine. Not Downloads, and not a OneDrive folder: if the folder moves or syncs away, the browser switches the extension off. -
Open
edge://extensions(orchrome://extensions) and turn on Developer mode — the switch in the bottom-left corner. -
Click “Load unpacked” and choose the
caretfolder. - Pin it from the puzzle-piece icon, then reload any tab you already had open. Start typing in any text box.
If it says “Manifest file is missing or unreadable” you picked the
wrong folder — go one level in. The folder you choose must have
manifest.json sitting directly inside it.
Privacy
It has nowhere to send your writing
The dictionary, the ninety-odd grammar rules and every suggestion are computed in your browser, on your machine. There is no server, no account, and no analytics — this page does not even load a font from somebody else's domain.
One optional exception, switched off until you turn it on yourself: add your own Anthropic API key and Caret can ask Claude for a second opinion on the field you are writing in. Even then it only runs when you press Alt+Shift+G, it is capped to a number of checks you choose, and password fields, card numbers and anything key-shaped are never sent.
Questions
The usual ones
Is it really free?
Yes. No paid tier, no trial, nothing to subscribe to. It was built for one person and given away as it is.
Where does it work?
Any ordinary text box on any site — e-mail, forms, comment boxes, rich editors — including boxes inside frames on a page.
It cannot work on browser pages themselves (edge://), on the extension store, or in editors that draw their own text on a canvas, Google Docs being the famous one. That is a browser rule, not a choice.
How do I change what it checks?
Toolbar button → Settings. Switch whole categories off, teach it your own words, silence it on particular sites, pick a straight or wavy underline. The setup guide walks through every one of them with pictures.
Why does it need “developer mode”?
Because it is loaded from a folder rather than from the store. Edge may occasionally ask whether you meant to keep developer-mode extensions on; clicking away from that prompt keeps Caret running.
How do I update it?
Download the new zip, replace the old folder with the new one, then press the reload arrow on the Caret card in edge://extensions.
Something is wrong with it. What do I do?
Tell me on the report page — what you typed, what it said, and which site you were on is plenty to go on.