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Browser Extensions · head to head

Greasemonkey vs Syft

Greasemonkey logo

Greasemonkey

Browser Extensions

The original userscript manager, for Firefox

From
Free
Rated
-
Full reviewWebsite
Syft logo

Syft

Cybersecurity

Generates a software bill of materials from images, filesystems and archives

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Greasemonkey firefox only. There is no Chrome, Edge or Safari build and there never has been.; Syft lockfile parsing can drop packages silently. An open issue filed in August 2026 reports the yarn v1 cataloguer returning 118 of 745 packages with no error raised, which means a complete bill of materials and an 84 percent incomplete one look identical to the caller.
  • They diverge on capability: Greasemonkey covers Userscript execution, Syft covers Multi-format output.
  • Prices and features above were last checked on 17 September 2026.

Where they differ

Only the attributes on which Greasemonkey and Syft actually diverge.

Attributes where Greasemonkey and Syft differ
AttributeGreasemonkeySyft
Pricing modelopen-sourceOpen source, no licence fee
PlatformsFirefoxmacOS, Linux, Windows, Docker
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 Greasemonkey

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

Only in Syft

  • Multi-format output
  • Broad ecosystem coverage
  • Binary classifiers
  • In-toto attestations
  • Library and CLI
  • Pairs with Grype

What people use each for

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

Greasemonkey

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

Syft

  • Producing a bill of materials for a customer or regulator that requires onenot Greasemonkey
  • Feeding an inventory into a vulnerability scanner rather than scanning images directlynot Greasemonkey
  • Recording what shipped in a build so a future disclosure can be answered quicklynot Greasemonkey
  • Public sector work where an SBOM is a contractual deliverablenot Greasemonkey

Where each one falls short

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

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.

Syft

  • Lockfile parsing can drop packages silently. An open issue filed in August 2026 reports the yarn v1 cataloguer returning 118 of 745 packages with no error raised, which means a complete bill of materials and an 84 percent incomplete one look identical to the caller.
  • Fidelity varies sharply by ecosystem. Conan for C and C++, Haskell and Terraform get cataloguer support with no licence data, no dependency relationships and no file ownership, so a C and C++ shop gets the least from it.
  • Binary classification yields no licence or dependency metadata, and vendored or statically linked code is exactly where supply chain risk hides, so the blind spot and the risk overlap.
  • Incorrect CPE values and CPE collisions are recorded as open issues, and since Grype matches on CPE and PURL, an inventory error becomes a false negative in the security report downstream.
  • An inventory is not a risk assessment. Even a perfect bill of materials says a vulnerable version is present, never that the vulnerable function is called, and the triage burden lands entirely on the reader.

Pricing, plan by plan

Greasemonkey

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

Syft

Free
  • SyftFree
    • Apache-2.0
    • No usage limits
    • Community support
  • Anchore Enterprise$undefined/year
    • Policy enforcement and reporting
    • Federal and commercial tiers
    • Pricing not published, quoted on request

Which should you pick?

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

Choose Syft if

  • You need multi-format output.
  • You want to start without paying.
  • You work on macOS, Linux, Windows, Docker.
  • You also want broad ecosystem coverage.
Syft review

Questions people ask

Is Greasemonkey or Syft better?
Neither clearly leads. Greasemonkey starts at Free and Syft at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Greasemonkey or Syft?
Greasemonkey starts at Free and Syft at Free.
Does Greasemonkey or Syft run on more platforms?
Greasemonkey runs on Firefox. Syft runs on macOS, Linux, Windows, Docker.
Can I use Greasemonkey for free?
Both have a free tier, so you can try either at no cost before committing.
What is Greasemonkey best used for?
Greasemonkey is most often used for restyling or de-cluttering a site you use daily, automating a repetitive action on a web application, adding a missing feature to a site you do not control, running userscripts on firefox for android. Of those, restyling or de-cluttering a site you use daily and automating a repetitive action on a web application are not what Syft is typically brought in for.
What can Greasemonkey do that Syft cannot?
Greasemonkey covers Userscript execution, Built-in script editor, GM. API, @resource support. Syft covers Multi-format output, Broad ecosystem coverage, Binary classifiers, In-toto attestations.

Answered from the vendors’ own pages

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
Syft: Does Syft find vulnerabilities?

No. It produces an inventory. Grype, from the same company, matches that inventory against vulnerability feeds. They are separate tools and the distinction is frequently lost.

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
Syft: Does anything in the Anchore stack do reachability analysis?

No. Neither Syft, Grype nor the commercial Anchore platform performs call graph or reachability analysis, so none of them tells you whether a vulnerable code path is actually invoked.

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
Syft: Is it a CNCF or OpenSSF project?

No. It is single-vendor open source owned by Anchore, with no foundation governance. That is a different licence risk profile from Sigstore.

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
Syft: What does Anchore Enterprise cost?

Not published. The pricing page is contact-sales only, with named but unpriced commercial and federal tiers.

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
Syft: How do I know my SBOM is complete?

You largely cannot, which is the honest answer. Silent partial parsing is a known open defect, so a bill of materials used for compliance should be spot-checked against a known dependency list.

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