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Browser Extensions · head to head

Greasemonkey vs Hemingway Editor

Greasemonkey logo

Greasemonkey

Browser Extensions

The original userscript manager, for Firefox

From
Free
Rated
-
Full reviewWebsite
Hemingway Editor logo

Hemingway Editor

Browser Extensions

Make your writing bold and clear

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.; Hemingway Editor no grammar or spelling corrections; tool focuses only on style, readability, and clarity, leaving grammatical errors unflagged
  • They diverge on capability: Greasemonkey covers Userscript execution, Hemingway Editor covers Readability analysis.
  • Prices and features above were last checked on 15 September 2026.

Where they differ

Only the attributes on which Greasemonkey and Hemingway Editor actually diverge.

Attributes where Greasemonkey and Hemingway Editor differ
AttributeGreasemonkeyHemingway Editor
Pricing modelopen-sourceUnknown
PlatformsFirefoxWeb, macOS, Windows
FoundedUnknown2013

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 Hemingway Editor

  • Readability analysis
  • Sentence complexity
  • Passive voice detection
  • Adverb highlighting
  • Chrome support
  • Firefox support
  • Edge 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 Hemingway Editor
  • Automating a repetitive action on a web applicationnot Hemingway Editor
  • Adding a missing feature to a site you do not controlnot Hemingway Editor
  • Running userscripts on Firefox for Androidnot Hemingway Editor
  • Writing and testing your own scripts in the browsernot Hemingway Editor

Hemingway Editor

  • Checking readability and flagging dense sentencesnot Greasemonkey
  • Grammar checking and proofreading a draftnot Greasemonkey
  • Adjusting tone before publishingnot Greasemonkey
  • Paraphrasing passages with the free web toolsnot 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.

Hemingway Editor

  • No grammar or spelling corrections; tool focuses only on style, readability, and clarity, leaving grammatical errors unflagged
  • Cannot distinguish context for idioms and colloquialisms, sometimes suggesting inappropriate replacements that alter intended meaning
  • Free version cannot suggest fixes for highlighted issues, only displays problems without solutions
  • Not suitable for academic or formal writing where its simplicity bias penalizes legitimate complex sentence structures

Pricing, plan by plan

Greasemonkey

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

Hemingway Editor

Free
  • FreeFree
    • Readability checking
    • Sentence highlighting
    • Adverb detection
  • Hemingway Editor Plus Individual 5K$8.33/month
    • 5,000 AI sentence rewrites monthly
    • Advanced grammar fixes (unlimited)
    • Unlimited document review
  • Hemingway Editor Plus Individual 10K$12.5/month
    • 10,000 AI sentence rewrites monthly
    • Advanced grammar fixes (unlimited)
    • Unlimited document review
  • Hemingway Editor Plus Team 10K$12.5/month
    • 10,000 AI sentence rewrites per user monthly
    • Role-based admin controls
    • Priority support

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 Hemingway Editor if

  • You need readability analysis.
  • You want to start without paying.
  • You work on Web, macOS, Windows.
  • You also want sentence complexity.
Hemingway Editor review

Questions people ask

Is Greasemonkey or Hemingway Editor better?
Neither clearly leads. Greasemonkey starts at Free and Hemingway Editor at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Greasemonkey or Hemingway Editor?
Greasemonkey starts at Free and Hemingway Editor at Free.
Does Greasemonkey or Hemingway Editor run on more platforms?
Greasemonkey runs on Firefox. Hemingway Editor runs on Web, macOS, Windows.
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 Hemingway Editor is typically brought in for.
What can Greasemonkey do that Hemingway Editor cannot?
Greasemonkey covers Userscript execution, Built-in script editor, GM. API, @resource support. Hemingway Editor covers Readability analysis, Sentence complexity, Passive voice detection, Adverb highlighting.

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
Hemingway Editor: Is there a free version and what does it include?

Yes. The free web version at hemingwayapp.com includes readability scoring, highlighting of complex sentences, passive voice detection, and weak adverb flagging. No account needed. Hemingway Editor Plus ($8.33/month or $100/year) adds advanced grammar fixes, AI sentence rewrites (10,000 monthly on best value plan), and unlimited document feedback.

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
Hemingway Editor: Does Hemingway Editor work offline?

The free web version requires internet. The desktop version for Mac and Windows ($19.99 one-time payment) works fully offline after download, enabling distraction-free writing without network connectivity.

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
Hemingway Editor: What writing metrics does Hemingway measure?

Hemingway grades readability level, highlights adverbs and weak words, flags passive voice constructions, marks complex or hard-to-read sentences in color (red for very hard, yellow for difficult), and suggests simpler alternatives for complex phrases.

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
Hemingway Editor: Can I collaborate with others or share documents?

The web version allows pasting text directly, but Hemingway Editor itself does not have native collaboration or team features. Team plans on Hemingway Plus support $12.50/user/month pricing and role-based admin controls, but are primarily for shared workspace management rather than live document collaboration.

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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