Grammar and Spell Checker - LanguageTool

Name: Grammar and Spell Checker - LanguageTool
Rating: 4.5829 (4992 reviews)
Author: LanguageTooler GmbH

With this extension you can check text with the 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.

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Features & Capabilities

Check your text across the web for grammar and spelling with LanguageTool. This extension catches errors that simple spell checkers miss, offers style suggestions, and supports 25+ languages. It works on Gmail, Facebook, X/Twitter, LinkedIn, and more, with no registration required.

LanguageTool provides American vs. British English variants, a personal dictionary, and privacy-conscious checks (no IP address stored). It analyzes text as you type and helps elevate your writing across many languages, making it useful for both native and non-native speakers.

User Growth & Download Statistics

Add-on Writing Education AI GenAI Privacy & Security

By:

Daily users:

Rating:

Version:

11.0.1 Last updated: 2026-05-22

Version code:

6268542

Creation date:

2016-06-10

Risk:

Permissions:

Content scripts matches:

*
docs.google.com
languagetool.org
localhost

Size:

15.06MB

URLs:

Website ,Privacy policy

Full description:

Source:

Firefox Add-ons Store

Data ingested on:

2026-06-18

Compare stats and ranking:

Ranking

# 44

Other rankings

#9 in Language Support

#19 in Social & Communication

#1 in ai spell checker keyword 76

#1 in ai spelling checker keyword 76

#1 in grammar & spelling keyword 66

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Other platforms

AI Grammar Checker & Paraphraser – LanguageTool (v11.0.0)

706,757 4.60

(610)

For Developers

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Contact the developer

Chrome-Stats does not own this Firefox add-on. Please use these information below to contact the Firefox add-on developer.

Developed by:

LanguageTooler GmbH

Firefox Add-ons Store

https://addons.mozilla.org/firefox/addon/languagetool/

Website:

https://languagetool.org/

Permission Change History

2025-04-07: Version 8.14.3 → 8.18.4

Add Permissions: scripting

2023-03-06: Version 6.0.1 → 6.2.2

Add Permissions: alarms

User Reviews

Users broadly praise Grammar and Spell Checker for being useful and grammar-aware, with features like custom sources and multilingual support. However, recurring concerns include heavy RAM usage causing browser crashes, occasional reliability problems, and occasional UI conflicts with other extensions.

Pros

Very useful, offering strong grammar understanding beyond a basic spell checker.
Unobtrusive in the browser, staying out of the way while you type.
Supports custom sources for checks.
Appears free for users (at least to some reviewers).
Strong language support, with positive notes about Catalan (and other languages).

Cons

High RAM usage leading to browser crashes (reported by multiple users).
Occasional reliability issues (false positives or missing mistakes) in some cases.
UI conflicts with other extensions (e.g., overlapping with the DeepL button).

Recent reviews

I have used this tool for a very long time, it worked as I wanted it to. But now I have to pay for it? What nonsense is that? I'll be removing this extension, and moving onto other tools that check spelling without some AI nonsense.

by Sa*****, 2026-06-17

by Fi*****, 2026-06-17

by Fa*****, 2026-06-17

View all user reviews ›

Is Grammar and Spell Checker - LanguageTool Safe?

Risk impact

Risk impact measures the level of extra permissions an extension has access to. A low risk impact extension cannot do much harms, whereas a high risk impact extension can do a lot of damage like stealing your password, bypassing your security settings, and accessing your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.

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

Risk likelihood measures the probability that a Firefox add-on may turn malicious. This is determined by the publisher and the Firefox add-on reputation on Firefox Add-ons Store, the amount of time the Firefox add-on has been around, and other signals about the Firefox add-on. Our algorithms are not perfect, and are subject to change as we discover new ways to detect malicious extensions. We recommend that you always exercise caution when installing a Firefox add-on.

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.
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