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Browser Extensions · head to head

Redux DevTools vs Userscripts

Redux DevTools logo

Redux DevTools

Browser Extensions

Debug Redux state changes in your browser

From
Free
Rated
-
Full reviewWebsite
Userscripts logo

Userscripts

Browser Extensions

Open-source userscript manager for Safari on Mac and iOS

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Redux DevTools significant performance overhead when tracking large state trees with many action history entries; Userscripts safari cannot let extensions bypass a site's Content Security Policy, so strict sites produce "Refused to execute a script" errors that the @inject-into workaround does not always fix.
  • They diverge on capability: Redux DevTools covers Action history, Userscripts covers Built-in script editor.
  • Prices and features above were last checked on 15 September 2026.

Where they differ

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

Attributes where Redux DevTools and Userscripts differ
AttributeRedux DevToolsUserscripts
PlatformsChrome, Firefox, Edge, ElectronSafari, macOS, iOS
Founded2015Unknown

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 Redux DevTools

  • Action history
  • State diff
  • Time-travel debugging
  • State export
  • Chrome support
  • Firefox support
  • Edge support

Only in Userscripts

  • Built-in script editor
  • Standard metadata support
  • GM API
  • Remote script updating
  • iCloud sync
  • Per-page popup

What people use each for

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

Redux DevTools

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

Userscripts

  • Running userscripts on Safari without paying for Tampermonkeynot Redux DevTools
  • Running userscripts on an iPhone or iPadnot Redux DevTools
  • Writing scripts on a Mac and syncing them to iOSnot Redux DevTools
  • Blocking or restyling site elements Safari content blockers cannot reachnot Redux DevTools
  • Keeping a script library under an open-source licencenot Redux DevTools

Where each one falls short

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

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

Userscripts

  • Safari cannot let extensions bypass a site's Content Security Policy, so strict sites produce "Refused to execute a script" errors that the @inject-into workaround does not always fix.
  • Apple only. There is no Chrome, Firefox or Edge build, so it cannot be a cross-browser answer.
  • iCloud sync is documented as having delays, which is awkward when editing the same script on two devices.
  • Requires macOS 12 and Safari 14.1, or iOS 15.1, so older Apple hardware is excluded.
  • GPL v3 means a commercial licence is required for non-open-source use, which matters if you are embedding rather than just using it.

Pricing, plan by plan

Redux DevTools

Free

No published plan breakdown. See the Redux DevTools review.

Userscripts

Free
  • FreeFree
    • Full functionality
    • GPL v3 licensed
    • macOS, iOS and iPadOS

Which should you pick?

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

Choose Userscripts if

  • You need built-in script editor.
  • You want to start without paying.
  • You work on Safari, macOS, iOS.
  • You also want standard metadata support.
Userscripts review

Questions people ask

Is Redux DevTools or Userscripts better?
Neither clearly leads. Redux DevTools starts at Free and Userscripts at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Redux DevTools or Userscripts?
Redux DevTools starts at Free and Userscripts at Free.
Does Redux DevTools or Userscripts run on more platforms?
Redux DevTools runs on Chrome, Firefox, Edge, Electron. Userscripts runs on Safari, macOS, iOS.
Can I use Redux DevTools for free?
Both have a free tier, so you can try either at no cost before committing.
What is Redux DevTools best used for?
Redux DevTools is most often used for redux development and debugging tool for javascript applications, action replay and time-travel debugging for state management. Of those, redux development and debugging tool for javascript applications and action replay and time-travel debugging for state management are not what Userscripts is typically brought in for.
What can Redux DevTools do that Userscripts cannot?
Redux DevTools covers Action history, State diff, Time-travel debugging, State export. Userscripts covers Built-in script editor, Standard metadata support, GM API, Remote script updating.

Answered from the vendors’ own pages

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
Userscripts: Is Userscripts for Safari free?

Yes, free on the App Store and licensed under GPL v3. A commercial licence is required for use in something that is not itself open source.

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
Userscripts: Does it work on iPhone?

Yes, on iOS and iPadOS 15.1 or later, which makes it one of the few ways to run userscripts on an iPhone.

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
Userscripts: Why do I get "Refused to execute a script" errors?

Safari does not let extensions bypass a site's Content Security Policy the way other browsers do. The documented workaround is changing the script's @inject-into setting, though it does not resolve every case.

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
Userscripts: Do my scripts sync between Mac and iPhone?

Yes, over iCloud, though the project notes the sync can be delayed rather than immediate.

Source
Userscripts: What are the system requirements?

macOS 12 or later with Safari 14.1 or later, or iOS and iPadOS 15.1 or later.

Source
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