LanguageTool

LanguageTool is a free grammar and style checker extension that catches the kinds of errors a simple spell checker simply cannot, helping you write with confidence every time you type online.

It supports more than 25 languages and works on almost any website, including Gmail, Facebook, and Twitter, so your emails, posts, and messages stay polished wherever you write.

LanguageTool identifies grammar issues, commonly confused words, and punctuation oversights, and goes further with helpful style suggestions such as synonym replacements, concise rephrasing, and formal alternatives for a more refined tone.

It also features a personal dictionary for your own terms and names, and it distinguishes between American and British English. And unlike Grammarly, QuillBot, and Ginger, LanguageTool supports a wider range of languages.