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Cybersecurity · head to head

Sigstore vs Userscripts

Sigstore logo

Sigstore

Cybersecurity

Free public signing and transparency infrastructure for open source artifacts

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: Sigstore the security model depends on somebody watching the log. The documentation states that compromise of an identity provider or of Fulcio itself is detectable only if third parties monitor the transparency log, the monitoring tool is a community-tier rather than core project, and almost no consumer runs one.; 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: Sigstore covers Fulcio, 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 Sigstore and Userscripts actually diverge.

Attributes where Sigstore and Userscripts differ
AttributeSigstoreUserscripts
Pricing modelOpen source, public instance free to useopen-source
PlatformsWeb, Linux, macOS, Windows, Self-hostedSafari, macOS, iOS
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 Sigstore

  • Fulcio
  • Rekor
  • Keyless signing
  • Multi-language clients
  • Timestamp authority
  • Neutral governance

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.

Sigstore

  • Open source projects signing releases without running a certificate authoritynot Userscripts
  • Organisations meeting a signed-artifact requirement without buying a signing productnot Userscripts
  • Publishing provenance that a consumer can verify independently of younot Userscripts
  • Self-hosting the same components where a public log is unacceptablenot Userscripts

Userscripts

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

Where each one falls short

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

Sigstore

  • The security model depends on somebody watching the log. The documentation states that compromise of an identity provider or of Fulcio itself is detectable only if third parties monitor the transparency log, the monitoring tool is a community-tier rather than core project, and almost no consumer runs one.
  • It is a 99.5 percent objective with no service level agreement, which permits several hours of downtime a month and offers no remedy. A pipeline that signs on every build has taken a hard dependency on a free service with no contract behind it.
  • Log scale is a live engineering problem rather than a theoretical one. The active shard holds billions of entries, the log has already been sharded twice, and sharding version 1 requires stopping traffic, which is why a replacement was built.
  • Ten-minute certificates make trust depend on log availability. Verifying an older signature relies on the log entry proving it was made inside that window, so a lost or unreachable entry can render a valid artifact unverifiable.
  • Migration debt is substantial and ongoing. Version 2 of the log is generally available but not the public default, the signing client has an announced breaking release ahead, some official clients lag the new log format, and a post-quantum migration is named as the next break after that.

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

Sigstore

Free
  • Public good instanceFree
    • Free to everyone with no contract
    • 99.5 percent availability objective, not an agreement
    • 100KB cap per attestation upload
  • Self-hostedFree
    • Apache-2.0
    • Run your own Fulcio and Rekor
    • Rekor v2 available for self-hosters

Userscripts

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

Which should you pick?

Choose Sigstore if

  • You need fulcio.
  • You want to start without paying.
  • You work on Web, Linux, macOS, Windows, Self-hosted.
  • You also want rekor.
Sigstore 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 Sigstore or Userscripts better?
Neither clearly leads. Sigstore 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, Sigstore or Userscripts?
Sigstore starts at Free and Userscripts at Free.
Does Sigstore or Userscripts run on more platforms?
Sigstore runs on Web, Linux, macOS, Windows, Self-hosted. Userscripts runs on Safari, macOS, iOS.
Can I use Sigstore for free?
Both have a free tier, so you can try either at no cost before committing.
What is Sigstore best used for?
Sigstore is most often used for open source projects signing releases without running a certificate authority, organisations meeting a signed-artifact requirement without buying a signing product, publishing provenance that a consumer can verify independently of you, self-hosting the same components where a public log is unacceptable. Of those, open source projects signing releases without running a certificate authority and organisations meeting a signed-artifact requirement without buying a signing product are not what Userscripts is typically brought in for.
What can Sigstore do that Userscripts cannot?
Sigstore covers Fulcio, Rekor, Keyless signing, Multi-language clients. Userscripts covers Built-in script editor, Standard metadata support, GM API, Remote script updating.

Answered from the vendors’ own pages

Sigstore: Is the public instance really free?

Yes, with no contract and no paid tier. That is also the weakness: a 99.5 percent objective with no agreement, no remedy and support through Slack.

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
Sigstore: Has the public log moved to Rekor v2?

No. Version 2 reached general availability in October 2025 and self-hosters can use it, but the public instance still defaults to version 1 and the project has said it will for the foreseeable future.

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
Sigstore: Does Sigstore make my dependencies safe?

No, and this is a category error worth avoiding. It tells you who published something. It has no knowledge of what the artifact contains or whether it is vulnerable.

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
Sigstore: What are the rate limits?

Not published. Only the 100KB cap per attestation upload is documented, so do not design a high-volume pipeline around assumed throughput.

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
Sigstore: Should we self-host it?

If a public record of every signature is unacceptable, or if a free service with no agreement cannot sit in your build path, then yes. Otherwise the public instance is what most projects use.

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
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