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Browser Extensions · head to head

FireMonkey vs Stay

FireMonkey logo

FireMonkey

Browser Extensions

User scripts and user styles in one Firefox extension

From
Free
Rated
-
Full reviewWebsite
Stay logo

Stay

Browser Extensions

Safari userscript manager that runs Tampermonkey scripts

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: FireMonkey firefox only, and requires a recent one: version 93 on desktop, 113 on Android.; Stay apple only. No Chrome, Firefox or Edge build, so it cannot serve a cross-browser workflow.
  • They diverge on capability: FireMonkey covers Scripts and styles together, Stay covers Tampermonkey and Violentmonkey compatibility.
  • Prices and features above were last checked on 15 September 2026.

Where they differ

Only the attributes on which FireMonkey and Stay actually diverge.

Attributes where FireMonkey and Stay differ
AttributeFireMonkeyStay
Pricing modelopen-sourceone-time
PlatformsFirefoxSafari, iOS, macOS

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 FireMonkey

  • Scripts and styles together
  • Monaco editor with ESLint
  • Unlimited client-side storage
  • Global injection
  • Notifications and clipboard
  • Firefox for Android

Only in Stay

  • Tampermonkey and Violentmonkey compatibility
  • Userscript management
  • Cross-device bookmark sync
  • Download manager
  • Dark mode
  • One-time purchase across platforms

What people use each for

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

FireMonkey

  • Running user scripts and user styles without two separate extensionsnot Stay
  • Restyling sites with CSS alongside scripted behaviour changesnot Stay
  • Editing scripts in a full editor inside the browsernot Stay
  • Injecting CSS globally across every sitenot Stay
  • Managing a mixed library of scripts and styles from one dashboardnot Stay

Stay

  • Running Tampermonkey scripts on Safarinot FireMonkey
  • Running userscripts on iPhone and iPadnot FireMonkey
  • Syncing bookmarks across Apple and non-Apple devicesnot FireMonkey
  • Managing downloads into categorised folders on iOSnot FireMonkey
  • Forcing dark mode on sites that do not offer itnot FireMonkey

Where each one falls short

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

FireMonkey

  • Firefox only, and requires a recent one: version 93 on desktop, 113 on Android.
  • Not a drop-in replacement for Greasemonkey, Tampermonkey or Stylus. The project says so itself, so an existing library may need adjusting.
  • A much smaller user base than Tampermonkey or Violentmonkey, which means fewer people have hit the bug you are about to hit.
  • No Chrome, Edge or Safari build, so it cannot be the answer for anyone working across browsers.
  • Combining scripts and styles in one extension also combines the blast radius: one extension with permission to inject both into every page.

Stay

  • Apple only. No Chrome, Firefox or Edge build, so it cannot serve a cross-browser workflow.
  • The free tier is deliberately limited, so the practical product is the paid one.
  • Compatibility with Tampermonkey and Violentmonkey scripts is a translation layer rather than the real thing, and a script relying on an unusual GM function may not behave identically.
  • It bundles bookmark sync, downloads and dark mode alongside the script manager, which is more surface area than some people want from an extension with access to every page.
  • A much smaller project than the established managers, so fewer scripts are tested against it.

Pricing, plan by plan

FireMonkey

Free
  • Open sourceFree
    • MPL-2.0 licensed
    • Unlimited scripts and styles
    • No account required

Stay

Free
  • FreeFree
    • Limited functionality
  • Lifetime$5/one-time
    • All features
    • iPhone, iPad and Mac
    • Lifetime updates

Which should you pick?

Choose FireMonkey if

  • You need scripts and styles together.
  • You want to start without paying.
  • You work on Firefox.
  • You also want monaco editor with eslint.
FireMonkey review

Choose Stay if

  • You need tampermonkey and violentmonkey compatibility.
  • You want to start without paying.
  • You work on Safari, iOS, macOS.
  • You also want userscript management.
Stay review

Questions people ask

Is FireMonkey or Stay better?
Neither clearly leads. FireMonkey starts at Free and Stay at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, FireMonkey or Stay?
FireMonkey starts at Free and Stay at Free.
Does FireMonkey or Stay run on more platforms?
FireMonkey runs on Firefox. Stay runs on Safari, iOS, macOS.
Can I use FireMonkey for free?
Both have a free tier, so you can try either at no cost before committing.
What is FireMonkey best used for?
FireMonkey is most often used for running user scripts and user styles without two separate extensions, restyling sites with css alongside scripted behaviour changes, editing scripts in a full editor inside the browser, injecting css globally across every site. Of those, running user scripts and user styles without two separate extensions and restyling sites with css alongside scripted behaviour changes are not what Stay is typically brought in for.
What can FireMonkey do that Stay cannot?
FireMonkey covers Scripts and styles together, Monaco editor with ESLint, Unlimited client-side storage, Global injection. Stay covers Tampermonkey and Violentmonkey compatibility, Userscript management, Cross-device bookmark sync, Download manager.

Answered from the vendors’ own pages

FireMonkey: What makes FireMonkey different from Violentmonkey?

It manages user styles as well as user scripts. The usual arrangement is a script manager plus a separate style manager such as Stylus; FireMonkey replaces both with one extension.

Source
Stay: Can Stay run Tampermonkey scripts?

Yes. It supports its own native scripts and also scripts written for Tampermonkey and Violentmonkey, which is the main reason to choose it on Safari.

Source
FireMonkey: Which browsers does FireMonkey support?

Firefox only. Desktop requires Firefox 93 or later and Android requires 113, with an API minimum of 102.

Source
Stay: How much does Stay cost?

A one-time payment, reported at around $5, covering iPhone, iPad and Mac with lifetime updates and no subscription. A free version with limited functionality is available.

Source
FireMonkey: Is FireMonkey open source?

Yes, under the MPL-2.0 licence.

Source
Stay: Does Stay work on iPhone?

Yes. It supports Safari across iPhone, iPad and Mac, and the single purchase covers all three.

Source
FireMonkey: Will my existing Tampermonkey scripts work?

Not necessarily. The project states that while it shares functionality with Greasemonkey, Tampermonkey and Stylus, there are differences, so scripts and styles written for those may need adjusting.

Source
Stay: What can userscripts do in Safari through Stay?

The vendor's examples are automatic pagination, immersive translation, redirect blocking and aggregated search. Anything a userscript can do on another browser is broadly in scope, subject to Safari's own restrictions.

Source
FireMonkey: What editor does FireMonkey use?

Current versions use the Monaco editor with ESLint, the same editor component that powers VS Code.

Source
Stay: Is Stay open source?

The project publishes source on GitHub, and the app is distributed through the App Store as a paid product with a limited free tier.

Source
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