Grammar and Spell Checker - LanguageTool

With this extension you can check text with the free style and grammar checker LanguageTool. It finds many errors that a simple spell checker cannot detect, like mixing up there/their, a/an, or repeating a word.

LanguageTool: Your Ultimate Grammar & Spell Checker

Grammar and Spell Checker - LanguageTool is a powerful Firefox add-on that helps you identify and correct spelling and grammar errors across the web. From social media to email clients like Gmail, LanguageTool enhances your writing in real-time, ensuring it is free from common mistakes such as confusing 'there' and 'their', or misusing articles like 'a' and 'an'. With support for over 25 languages, it is perfect for non-native speakers and native users alike.

The extension offers advanced features like style suggestions, synonym replacements, and the ability to customize a personal dictionary for unique terms. Privacy is a priority, as LanguageTool processes text over an encrypted connection without storing user data. This extension is not just another spell checker; it’s a comprehensive tool that elevates your writing while providing confidence in your content.

Manifest V3
Daily users: 401,186
-2,739
Version: 8.18.4 (Last updated: 2025-04-07)
Version code: 5908022
Creation date: 2016-06-10
Weekly download count: 8,069
Firefox on Android: No
Permissions:
  • activeTab
  • storage
  • contextMenus
  • scripting
  • alarms
Size: 14.57M
Full description: See detailed description
Updated: 20 hours ago

Other platforms

User reviews

Pros
  • Works well and is not intrusive to the user experience
  • Allows users to add to the dictionary
  • Fast analysis and corrections
  • Cost-effective service
  • Helps with numerous errors and typos
Cons
  • Sometimes misses obvious spelling mistakes
  • Not functioning in all text areas
  • Lacks support for some languages (e.g., Czech, Canadian French)
  • Has experienced issues with formatting corrections in recent updates
  • Occasional incorrect corrections or suggestions
Most mentioned
  • The effectiveness of spell checking and grammar correction
  • The ability to customize the dictionary
  • Intrusiveness of the application
  • Issues with language support
  • Problems with formatting corrections
These summaries are automatically generated weekly using AI based on recent user reviews. User reviews may be inaccurate, spammy, or outdated.
User reviews
by Zigurds, 2025-04-07


Vey good tool thanks journalistech.com
by JournalisTech, 2025-04-06
View all user reviews

Add-on safety

Risk impact
High risk impact

Grammar and Spell Checker - LanguageTool requires some sensitive permissions that could impact your browser and data security. Exercise caution before installing.

Risk impact analysis details
  • Critical Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
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Risk likelihood
Low risk likelihood

Grammar and Spell Checker - LanguageTool has earned a fairly good reputation and likely can be trusted.

Risk likelihood analysis details
  • High This extension was recently updated in the past month. New updates may not be stable or safe.
  • Low **** ********* *** ***** **** **** * ****** **** ***** ********** *** **** ****** ** ** ****** *** *****
  • Low **** ********* *** **** **** ****** ******* ********** **** ****** ** ** ****** *** *****
  • Good **** ********* *** **** **** *******
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