Softwr

Technology · head to head

Mozilla Firefox vs Userscripts

Mozilla Firefox logo

Mozilla Firefox

Technology

An independent web browser with its own rendering engine, funded almost entirely by search placement deals.

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: Mozilla Firefox roughly 85 per cent of Mozilla's revenue comes from search default placement deals, overwhelmingly with Google, so the organisation that competes with Chrome depends on Chrome's owner for its funding and any renegotiation lands on Firefox's engineering budget within a quarter.; 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: Mozilla Firefox covers Gecko engine, Userscripts covers Built-in script editor.
  • Prices and features above were last checked on 17 September 2026.

Where they differ

Only the attributes on which Mozilla Firefox and Userscripts actually diverge.

Attributes where Mozilla Firefox and Userscripts differ
AttributeMozilla FirefoxUserscripts
Pricing modelUnknownopen-source
PlatformsWindows, macOS, Linux, iOS, AndroidSafari, macOS, iOS
CategoryTechnologyBrowser Extensions
Founded2004Unknown

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

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 Mozilla Firefox

  • Gecko engine
  • Full webRequest blocking
  • Total Cookie Protection
  • Container tabs
  • Extended Support Release
  • policies.json and ADMX
  • Built-in developer tools
  • Firefox Sync

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.

Mozilla Firefox

  • Web development where you need to test against a non-Chromium engine before shipping, because Chromium-only testing hides real bugsnot Userscripts
  • Users who require a full-strength content blocker, which Chrome's Manifest V3 no longer permitsnot Userscripts
  • Managed fleets that need a browser on a slow release cadence with Group Policy control, using the ESR channelnot Userscripts
  • Handling several accounts on the same service at once through container tabs, without separate profiles or private windowsnot Userscripts

Userscripts

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

Where each one falls short

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

Mozilla Firefox

  • Roughly 85 per cent of Mozilla's revenue comes from search default placement deals, overwhelmingly with Google, so the organisation that competes with Chrome depends on Chrome's owner for its funding and any renegotiation lands on Firefox's engineering budget within a quarter.
  • Desktop market share sits at a few per cent, so commercial sites are tested against Chrome and Safari and a Firefox-only rendering or WebRTC bug is triaged as low priority by the site owner, leaving you with the workaround.
  • On iOS and iPadOS the browser is a WebKit shell required by Apple's rules, so it delivers the interface and Sync but none of the engine, extension or tracking-protection behaviour that make Firefox worth choosing on desktop.
  • Mozilla declines to implement several hardware-facing APIs on principle, including WebUSB, WebSerial, Web Bluetooth and WebHID, so a web application that talks to a device simply does not run and no configuration flag changes that.
  • Enterprise management is limited to policies.json and ADMX templates; there is no first-party equivalent of Chrome Browser Cloud Management, so fleet-wide reporting on versions and extensions requires third-party tooling you have to buy or build.
  • Mozilla repeatedly ships decisions its own user base objects to, such as enabling Privacy Preserving Attribution by default and the 2025 Terms of Use rewrite, and reversals arrive after the news cycle, so deploying it on a privacy argument means owning the communications work each time.

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

Mozilla Firefox

Free

No published plan breakdown. See the Mozilla Firefox review.

Userscripts

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

Which should you pick?

Choose Mozilla Firefox if

  • You need gecko engine.
  • You want to start without paying.
  • You work on Windows, macOS, Linux, iOS, Android.
  • You also want full webrequest blocking.
Mozilla Firefox 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 Mozilla Firefox or Userscripts better?
Neither clearly leads. Mozilla Firefox 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, Mozilla Firefox or Userscripts?
Mozilla Firefox starts at Free and Userscripts at Free.
Does Mozilla Firefox or Userscripts run on more platforms?
Mozilla Firefox runs on Windows, macOS, Linux, iOS, Android. Userscripts runs on Safari, macOS, iOS.
Can I use Mozilla Firefox for free?
Both have a free tier, so you can try either at no cost before committing.
What is Mozilla Firefox best used for?
Mozilla Firefox is most often used for web development where you need to test against a non-chromium engine before shipping, because chromium-only testing hides real bugs, users who require a full-strength content blocker, which chrome's manifest v3 no longer permits, managed fleets that need a browser on a slow release cadence with group policy control, using the esr channel, handling several accounts on the same service at once through container tabs, without separate profiles or private windows. Of those, web development where you need to test against a non-chromium engine before shipping, because chromium-only testing hides real bugs and users who require a full-strength content blocker, which chrome's manifest v3 no longer permits are not what Userscripts is typically brought in for.
What can Mozilla Firefox do that Userscripts cannot?
Mozilla Firefox covers Gecko engine, Full webRequest blocking, Total Cookie Protection, Container tabs. Userscripts covers Built-in script editor, Standard metadata support, GM API, Remote script updating.

Answered from the vendors’ own pages

Mozilla Firefox: Does uBlock Origin still work on Firefox?

Yes. Firefox has kept the blocking webRequest API that Chrome removed with Manifest V3, so uBlock Origin runs with its full rule set rather than the cut-down Lite version Chrome requires.

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
Mozilla Firefox: Is Firefox on iPhone the same browser?

No. Apple's platform rules require it to use WebKit, so on iOS and iPadOS you get Firefox's interface, Sync and bookmarks on top of Safari's engine. The privacy and extension behaviour are not the same.

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
Mozilla Firefox: How is Mozilla funded, and does that matter?

Mainly by payments for making a search engine the default, with Google as the dominant payer. It matters because it is a single-source dependency on a direct competitor, and it has been the subject of antitrust litigation whose outcome Mozilla does not control.

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
Mozilla Firefox: Can I manage it across a company fleet?

Yes, through policies.json or Windows Group Policy with the ADMX templates, and the ESR channel gives you a roughly yearly major version instead of four-weekly. There is no first-party cloud management console, so reporting needs other tooling.

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
Mozilla Firefox: Will every site work in it?

Most will. The exceptions cluster around sites tested only in Chrome, legacy enterprise applications, and anything using WebUSB, WebSerial, Web Bluetooth or WebHID, which Firefox does not implement at all.

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
Share

Related pages

More on Mozilla Firefox

More on Userscripts

Keep looking

Other head to heads