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Browser Extensions · head to head

FireMonkey vs Logto

FireMonkey logo

FireMonkey

Browser Extensions

User scripts and user styles in one Firefox extension

From
Free
Rated
-
Full reviewWebsite
Logto logo

Logto

Cybersecurity

Open-source identity and authentication infrastructure for apps and APIs

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.; Logto advanced features like RBAC, organizations, MFA, and enterprise SSO are billed as separate paid add-ons rather than included in Pro.
  • They diverge on capability: FireMonkey covers Scripts and styles together, Logto covers Prebuilt sign-in UI.
  • Prices and features above were last checked on 15 September 2026.

Where they differ

Only the attributes on which FireMonkey and Logto actually diverge.

Attributes where FireMonkey and Logto differ
AttributeFireMonkeyLogto
Pricing modelopen-sourcefreemium
PlatformsFirefoxweb, api
CategoryBrowser ExtensionsCybersecurity

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 FireMonkey

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

Only in Logto

  • Prebuilt sign-in UI
  • Social connectors
  • Role-based access control
  • Multi-factor authentication
  • Machine-to-machine apps
  • Audit logs

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 Logto
  • Restyling sites with CSS alongside scripted behaviour changesnot Logto
  • Editing scripts in a full editor inside the browsernot Logto
  • Injecting CSS globally across every sitenot Logto
  • Managing a mixed library of scripts and styles from one dashboardnot Logto

Logto

  • Adding sign-in to a new SaaS productnot FireMonkey
  • Implementing SSO for B2B customersnot FireMonkey
  • Securing internal APIs with M2M tokensnot FireMonkey
  • Adding RBAC and organizations to a multi-tenant appnot 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.

Logto

  • Advanced features like RBAC, organizations, MFA, and enterprise SSO are billed as separate paid add-ons rather than included in Pro.
  • Enterprise pricing is not published and requires contacting sales.
  • Token-based billing can make cost forecasting harder than flat per-MAU pricing for high-traffic apps.

Pricing, plan by plan

FireMonkey

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

Logto

Free
  • FreeFree
    • Up to 50,000 MAU
    • 50K tokens included
    • 3 applications
  • Pro$24/month
    • Unlimited MAU and applications
    • 3 included API resources
    • Passkey sign-in

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 Logto if

  • You need prebuilt sign-in ui.
  • You want to start without paying.
  • You work on web, api.
  • You also want social connectors.
Logto review

Questions people ask

Is FireMonkey or Logto better?
Neither clearly leads. FireMonkey starts at Free and Logto at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, FireMonkey or Logto?
FireMonkey starts at Free and Logto at Free.
Does FireMonkey or Logto run on more platforms?
FireMonkey runs on Firefox. Logto runs on web, api.
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 Logto is typically brought in for.
What can FireMonkey do that Logto cannot?
FireMonkey covers Scripts and styles together, Monaco editor with ESLint, Unlimited client-side storage, Global injection. Logto covers Prebuilt sign-in UI, Social connectors, Role-based access control, Multi-factor authentication.

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
Logto: What does Logto cost?

Logto offers a Free plan at $0/month, a Pro plan starting at $24/month with 50K free tokens included, and a custom-priced Enterprise plan. Extra add-ons like RBAC or MFA are billed separately on Pro.

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
Logto: Is there a free plan, and what are its limits?

Yes. The Free plan supports up to 50,000 monthly active users, 3 total applications, 1 machine-to-machine app, 3 social connectors, 1 webhook, and 3-day audit log retention.

Source
FireMonkey: Is FireMonkey open source?

Yes, under the MPL-2.0 licence.

Source
Logto: How is usage metered?

Logto uses token-based billing: only access tokens issued for authentication and authorization activity are counted, rather than charging purely per MAU.

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
FireMonkey: What editor does FireMonkey use?

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

Source
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