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Browser Extensions · head to head

Greasemonkey vs LanguageTool

Greasemonkey logo

Greasemonkey

Browser Extensions

The original userscript manager, for Firefox

From
Free
Rated
-
Full reviewWebsite
LanguageTool logo

LanguageTool

Browser Extensions

Grammar and spell checker for 25+ languages

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Greasemonkey firefox only. There is no Chrome, Edge or Safari build and there never has been.; LanguageTool free tier limited to basic spelling and simple punctuation; advanced punctuation and style issues caught only on premium
  • They diverge on capability: Greasemonkey covers Userscript execution, LanguageTool covers Multi-language support.
  • Prices and features above were last checked on 15 September 2026.

Where they differ

Only the attributes on which Greasemonkey and LanguageTool actually diverge.

Attributes where Greasemonkey and LanguageTool differ
AttributeGreasemonkeyLanguageTool
Pricing modelopen-sourcefreemium
PlatformsFirefoxWeb editor, Windows desktop app, macOS desktop app, Chrome extension, Firefox extension, Edge extension, Safari extension, Opera extension, Google Docs, Microsoft Word, iOS app
FoundedUnknown2003

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Browser Extensions).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Greasemonkey

  • Userscript execution
  • Built-in script editor
  • GM. API
  • @resource support
  • Script localisation
  • Firefox for Android

Only in LanguageTool

  • Multi-language support
  • Grammar checking
  • Style suggestions
  • Personal dictionary
  • Chrome support
  • Firefox support
  • Edge support
  • Safari support

What people use each for

The jobs each tool is most often brought in to do.

Greasemonkey

  • Restyling or de-cluttering a site you use dailynot LanguageTool
  • Automating a repetitive action on a web applicationnot LanguageTool
  • Adding a missing feature to a site you do not controlnot LanguageTool
  • Running userscripts on Firefox for Androidnot LanguageTool
  • Writing and testing your own scripts in the browsernot LanguageTool

LanguageTool

  • Grammar and spelling correction across web and desktopnot Greasemonkey
  • Style and clarity improvementsnot Greasemonkey
  • Multilingual writing assistancenot Greasemonkey

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Greasemonkey

  • Firefox only. There is no Chrome, Edge or Safari build and there never has been.
  • Its API diverged from the Tampermonkey conventions most shared scripts are written against, so a script from a sharing site may need adjusting to run.
  • The dashboard is plainer than Tampermonkey's, with no diff view when a script updates itself.
  • No cloud sync of the kind Tampermonkey and Violentmonkey offer; moving machines means exporting.
  • A userscript manager can read and rewrite every page you visit, so the security of the arrangement depends entirely on the scripts you choose to install.

LanguageTool

  • Free tier limited to basic spelling and simple punctuation; advanced punctuation and style issues caught only on premium
  • Picky Mode (advanced typography) unavailable on free plan
  • Specific pricing not displayed on main page; requires navigation to purchase flow

Pricing, plan by plan

Greasemonkey

Free
  • Open sourceFree
    • Unlimited scripts
    • Built-in editor
    • No account required

LanguageTool

Free
  • BasicFree
    • 2,000 character limit per text
    • 3 AI paraphrasing requests per day
    • Basic grammar and spelling checks
  • Premium$null/month
    • 150,000 character limit per text
    • Unlimited AI paraphrasing
    • 20,000+ grammar and style checks
  • Teams$null/month
    • Per-user, per-month pricing
    • 2-1000+ users
    • Team Style Guide

Which should you pick?

Choose Greasemonkey if

  • You need userscript execution.
  • You want to start without paying.
  • You work on Firefox.
  • You also want built-in script editor.
Greasemonkey review

Choose LanguageTool if

  • You need multi-language support.
  • You want to start without paying.
  • You work on Web editor, Windows desktop app, macOS desktop app, Chrome extension, Firefox extension, Edge extension, Safari extension, Opera extension, Google Docs, Microsoft Word, iOS app.
  • You also want grammar checking.
LanguageTool review

Questions people ask

Is Greasemonkey or LanguageTool better?
Neither clearly leads. Greasemonkey starts at Free and LanguageTool at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Greasemonkey or LanguageTool?
Greasemonkey starts at Free and LanguageTool at Free.
Does Greasemonkey or LanguageTool run on more platforms?
Greasemonkey runs on Firefox. LanguageTool runs on Web editor, Windows desktop app, macOS desktop app, Chrome extension, Firefox extension, Edge extension, Safari extension, Opera extension, Google Docs, Microsoft Word, iOS app.
Can I use Greasemonkey for free?
Both have a free tier, so you can try either at no cost before committing.
What is Greasemonkey best used for?
Greasemonkey is most often used for restyling or de-cluttering a site you use daily, automating a repetitive action on a web application, adding a missing feature to a site you do not control, running userscripts on firefox for android. Of those, restyling or de-cluttering a site you use daily and automating a repetitive action on a web application are not what LanguageTool is typically brought in for.
What can Greasemonkey do that LanguageTool cannot?
Greasemonkey covers Userscript execution, Built-in script editor, GM. API, @resource support. LanguageTool covers Multi-language support, Grammar checking, Style suggestions, Personal dictionary.

Answered from the vendors’ own pages

Greasemonkey: Is Greasemonkey still maintained?

Yes. Version 4.14 was released on 2 June 2026, and the project has an active repository, bug tracker and discussion groups.

Source
LanguageTool: Does LanguageTool have a free version?

Yes, LanguageTool Basic is free with a 2,000 character limit per text field and 3 AI paraphrasing requests per day for basic grammar and spelling checks.

Source
Greasemonkey: Does Greasemonkey work on Chrome?

No. It is a Firefox extension and has never shipped for Chrome. Violentmonkey and Tampermonkey are the equivalents there.

Source
LanguageTool: What does LanguageTool Premium offer?

LanguageTool Premium increases the character limit to 150,000 per text field, provides unlimited AI paraphrasing, and includes 20,000+ advanced grammar and style checks. Multiple billing options are available including monthly, quarterly, annual, and 2-year plans.

Source
Greasemonkey: Will Tampermonkey scripts run in Greasemonkey?

Often, but not always. Greasemonkey's API diverged from the conventions most shared scripts are written against, so a script may need its header or its GM calls adjusted.

Source
LanguageTool: Does LanguageTool offer a money-back guarantee?

Yes, LanguageTool provides a 14-day money-back guarantee on all Premium packages with no period of notice required; cancel anytime.

Source
Greasemonkey: Does Greasemonkey run on mobile?

On Firefox for Android, from version 4.12. There is no iOS build, because Firefox on iOS cannot load extensions of this kind.

Source
Greasemonkey: What is the GM API?

The set of functions a userscript manager exposes to scripts, named after Greasemonkey, which defined it. Greasemonkey supports the promise-based GM. form including GM.xmlHttpRequest and GM.registerMenuCommand.

Source
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