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Browser Extensions · head to head

Greasemonkey vs Redux DevTools

Greasemonkey logo

Greasemonkey

Browser Extensions

The original userscript manager, for Firefox

From
Free
Rated
-
Full reviewWebsite
Redux DevTools logo

Redux DevTools

Browser Extensions

Debug Redux state changes in your browser

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.; Redux DevTools significant performance overhead when tracking large state trees with many action history entries
  • They diverge on capability: Greasemonkey covers Userscript execution, Redux DevTools covers Action history.
  • Prices and features above were last checked on 15 September 2026.

Where they differ

Only the attributes on which Greasemonkey and Redux DevTools actually diverge.

Attributes where Greasemonkey and Redux DevTools differ
AttributeGreasemonkeyRedux DevTools
PlatformsFirefoxChrome, Firefox, Edge, Electron
FoundedUnknown2015

Identical on both: starting price (Free), pricing model (open-source), 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 Redux DevTools

  • Action history
  • State diff
  • Time-travel debugging
  • State export
  • 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 Redux DevTools
  • Automating a repetitive action on a web applicationnot Redux DevTools
  • Adding a missing feature to a site you do not controlnot Redux DevTools
  • Running userscripts on Firefox for Androidnot Redux DevTools
  • Writing and testing your own scripts in the browsernot Redux DevTools

Redux DevTools

  • Redux development and debugging tool for JavaScript applicationsnot Greasemonkey
  • Action replay and time-travel debugging for state managementnot 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.

Redux DevTools

  • Significant performance overhead when tracking large state trees with many action history entries
  • Memory consumption increases with action history, especially with large datasets of 11,000+ records
  • UI becomes sluggish when LogMonitor contains many actions in history
  • Requires manual configuration of maxAge and sanitizers to optimize performance

Pricing, plan by plan

Greasemonkey

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

Redux DevTools

Free

No published plan breakdown. See the Redux DevTools review.

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 Redux DevTools if

  • You need action history.
  • You want to start without paying.
  • You work on Chrome, Firefox, Edge, Electron.
  • You also want state diff.
Redux DevTools review

Questions people ask

Is Greasemonkey or Redux DevTools better?
Neither clearly leads. Greasemonkey starts at Free and Redux DevTools at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Greasemonkey or Redux DevTools?
Greasemonkey starts at Free and Redux DevTools at Free.
Does Greasemonkey or Redux DevTools run on more platforms?
Greasemonkey runs on Firefox. Redux DevTools runs on Chrome, Firefox, Edge, Electron.
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 Redux DevTools is typically brought in for.
What can Greasemonkey do that Redux DevTools cannot?
Greasemonkey covers Userscript execution, Built-in script editor, GM. API, @resource support. Redux DevTools covers Action history, State diff, Time-travel debugging, State export.

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
Redux DevTools: Is Redux DevTools free?

Yes, Redux DevTools is completely free and open-source under the MIT license. It is available as a browser extension for Chrome, Firefox, and Edge, and can also be used as a standalone app or React component.

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
Redux DevTools: What browsers does Redux DevTools support?

Redux DevTools is available as a browser extension for Chrome, Firefox, and Edge. It can also be integrated directly into applications as a React component or standalone app.

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
Redux DevTools: Does Redux DevTools work with production builds?

Redux DevTools is designed for development and should be disabled in production builds. Keeping it enabled in production can impact application performance due to state logging overhead.

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
Redux DevTools: How do I enable time-travel debugging with Redux DevTools?

Redux DevTools allows you to step back through dispatched actions, canceling actions to return to previous application states. This time-travel debugging is built into the core functionality of the extension.

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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