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Cybersecurity · head to head

Authelia vs Greasemonkey

Authelia logo

Authelia

Cybersecurity

Open-source authentication and two-factor portal for reverse proxies

From
Free
Rated
-
Full reviewWebsite
Greasemonkey logo

Greasemonkey

Browser Extensions

The original userscript manager, for Firefox

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Authelia depends on a reverse proxy: it is not a standalone identity provider; Greasemonkey firefox only. There is no Chrome, Edge or Safari build and there never has been.
  • They diverge on capability: Authelia covers Reverse proxy integration, Greasemonkey covers Userscript execution.
  • Prices and features above were last checked on 17 September 2026.

Where they differ

Only the attributes on which Authelia and Greasemonkey actually diverge.

Attributes where Authelia and Greasemonkey differ
AttributeAutheliaGreasemonkey
Pricing modelOpen source, no licence feeopen-source
PlatformsDocker, Kubernetes, Linux, Self-hostedFirefox
CategoryCybersecurityBrowser Extensions

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 Authelia

  • Reverse proxy integration
  • Two-factor authentication
  • Access control rules
  • Lightweight backends

Only in Greasemonkey

  • Userscript execution
  • Built-in script editor
  • GM. API
  • @resource support
  • Script localisation
  • Firefox for Android

What people use each for

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

Authelia

  • Putting a login and 2FA in front of self-hosted services that have nonenot Greasemonkey
  • Adding SSO across a small set of internal tools without a full identity platformnot Greasemonkey
  • Home and small-team infrastructure behind a single reverse proxynot Greasemonkey

Greasemonkey

  • Restyling or de-cluttering a site you use dailynot Authelia
  • Automating a repetitive action on a web applicationnot Authelia
  • Adding a missing feature to a site you do not controlnot Authelia
  • Running userscripts on Firefox for Androidnot Authelia
  • Writing and testing your own scripts in the browsernot Authelia

Where each one falls short

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

Authelia

  • Depends on a reverse proxy: it is not a standalone identity provider
  • Configuration is YAML-first with no administrative interface, so changes mean editing files
  • Not a full IAM: user management, provisioning and federation are limited compared with Keycloak
  • Scales poorly as an organisation-wide identity solution, which is not its target

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.

Pricing, plan by plan

Authelia

Free
  • AutheliaFree
    • Full functionality
    • No usage limits
    • Community support

Greasemonkey

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

Which should you pick?

Choose Authelia if

  • You need reverse proxy integration.
  • You want to start without paying.
  • You work on Docker, Kubernetes, Linux, Self-hosted.
  • You also want two-factor authentication.
Authelia review

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

Questions people ask

Is Authelia or Greasemonkey better?
Neither clearly leads. Authelia starts at Free and Greasemonkey at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Authelia or Greasemonkey?
Authelia starts at Free and Greasemonkey at Free.
Does Authelia or Greasemonkey run on more platforms?
Authelia runs on Docker, Kubernetes, Linux, Self-hosted. Greasemonkey runs on Firefox.
Can I use Authelia for free?
Both have a free tier, so you can try either at no cost before committing.
What is Authelia best used for?
Authelia is most often used for putting a login and 2fa in front of self-hosted services that have none, adding sso across a small set of internal tools without a full identity platform, home and small-team infrastructure behind a single reverse proxy. Of those, putting a login and 2fa in front of self-hosted services that have none and adding sso across a small set of internal tools without a full identity platform are not what Greasemonkey is typically brought in for.
What can Authelia do that Greasemonkey cannot?
Authelia covers Reverse proxy integration, Two-factor authentication, Access control rules, Lightweight backends. Greasemonkey covers Userscript execution, Built-in script editor, GM. API, @resource support.

Answered from the vendors’ own pages

Authelia: Is Authelia free?

Yes, open source with no licence fee.

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
Authelia: Does Authelia need a reverse proxy?

Yes. It integrates through forward authentication with Nginx, Traefik, Caddy or HAProxy rather than sitting in front of traffic itself.

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
Authelia: Authelia or Keycloak?

Authelia is far lighter and aimed at protecting self-hosted services behind a proxy. Keycloak is a full identity and access management platform, and much more to run.

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
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
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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