Cybersecurity · head to head
Cosign vs Violentmonkey
Cosign
Cybersecurity
Signs and verifies container images and artifacts, with or without managing keys
- From
- Free
- Rated
- -
The short version
- Each has a real cost: Cosign keyless signing inherits every weakness of the identity provider behind it. Sigstore’s own threat model states that if an identity provider is compromised, Sigstore will issue certificates to those identities, so a compromised account produces perfectly valid signatures.; Violentmonkey smaller script ecosystem compared to Tampermonkey which has larger user base and more available scripts
- They diverge on capability: Cosign covers Keyless signing, Violentmonkey covers Userscript support.
- Prices and features above were last checked on 31 August 2026.
Where they differ
Only the attributes on which Cosign and Violentmonkey actually diverge.
| Attribute | Cosign | Violentmonkey |
|---|---|---|
| Pricing model | Open source, no licence fee | Unknown |
| Platforms | macOS, Linux, Windows, Docker | Chrome, Firefox, Edge |
| Category | Cybersecurity | Browser Extensions |
| Founded | Unknown | 2013 |
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 Cosign
- Keyless signing
- Key and KMS signing
- Registry-native storage
- In-toto attestations
- Offline verification
- Trusted root and signing config
Only in Violentmonkey
- Userscript support
- Clean interface
- Cloud sync
- Script editor
- Chrome support
- Firefox support
- Edge support
- Opera support
What people use each for
The jobs each tool is most often brought in to do.
Cosign
- Signing container images in a build pipeline without managing long-lived private keysnot Violentmonkey
- Attaching a signed bill of materials to a release so consumers can verify its provenancenot Violentmonkey
- Meeting a customer or regulatory requirement for signed artifactsnot Violentmonkey
- Verifying third-party images before they enter an internal registrynot Violentmonkey
Violentmonkey
- Run open-source userscripts to customize or automate web pagesnot Cosign
- Import scripts compatible with Greasemonkey and Tampermonkey formatsnot Cosign
- Sync scripts and settings across browsers via Dropbox, OneDrive, Google Drive, or WebDAVnot Cosign
- Batch import/export scripts as zip filesnot Cosign
Where each one falls short
Documented limitations, not opinions. Every one is a constraint you would hit in normal use.
Cosign
- Keyless signing inherits every weakness of the identity provider behind it. Sigstore’s own threat model states that if an identity provider is compromised, Sigstore will issue certificates to those identities, so a compromised account produces perfectly valid signatures.
- A signature proves who signed, never whether they should have. The documentation is explicit that Sigstore cannot determine authorisation, so every consumer must write and maintain their own identity and issuer policy or verification means nothing.
- Nothing is enforced without an admission controller. Signing changes what you can prove, not what runs, and the official policy controller has a small maintainer base for a component sitting in a cluster admission path.
- Upgrades break pipelines. Version 3 changed defaults, version 4 is announced as removing legacy functionality and roughly half the command line flags, and two official client libraries still lacked support for the new log format as of mid 2026.
- Signatures do not expire. An artifact signed before a maintainer account was compromised and one signed after are indistinguishable unless somebody is actively monitoring the transparency log, and almost nobody is.
Violentmonkey
- Smaller script ecosystem compared to Tampermonkey which has larger user base and more available scripts
- Less marketing and visibility results in lower adoption compared to more widely-known alternatives
- Community maintenance model means slower feature development compared to commercial alternatives
Pricing, plan by plan
Cosign
Free- CosignFree
- Apache-2.0
- Public Sigstore infrastructure free to use
- No usage limits published
Violentmonkey
FreeNo published plan breakdown. See the Violentmonkey review.
Which should you pick?
Choose Cosign if
- You need keyless signing.
- You want to start without paying.
- You work on macOS, Linux, Windows, Docker.
- You also want key and kms signing.
Choose Violentmonkey if
- You need userscript support.
- You want to start without paying.
- You work on Chrome, Firefox, Edge.
- You also want clean interface.
Questions people ask
- Is Cosign or Violentmonkey better?
- Neither clearly leads. Cosign starts at Free and Violentmonkey at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
- Which is cheaper, Cosign or Violentmonkey?
- Cosign starts at Free and Violentmonkey at Free.
- Does Cosign or Violentmonkey run on more platforms?
- Cosign runs on macOS, Linux, Windows, Docker. Violentmonkey runs on Chrome, Firefox, Edge.
- Can I use Cosign for free?
- Both have a free tier, so you can try either at no cost before committing.
- What is Cosign best used for?
- Cosign is most often used for signing container images in a build pipeline without managing long-lived private keys, attaching a signed bill of materials to a release so consumers can verify its provenance, meeting a customer or regulatory requirement for signed artifacts, verifying third-party images before they enter an internal registry. Of those, signing container images in a build pipeline without managing long-lived private keys and attaching a signed bill of materials to a release so consumers can verify its provenance are not what Violentmonkey is typically brought in for.
- What can Cosign do that Violentmonkey cannot?
- Cosign covers Keyless signing, Key and KMS signing, Registry-native storage, In-toto attestations. Violentmonkey covers Userscript support, Clean interface, Cloud sync, Script editor.
Answered from the vendors’ own pages
Cosign: Does Cosign tell me if an image is vulnerable?
No. It has no vulnerability knowledge whatsoever. It can carry an SBOM as a signed attestation but never reads it. Pair it with a scanner.
Violentmonkey: Is Violentmonkey open-source?
Yes. Violentmonkey is fully open-source and available on GitHub, making it free to use and community-maintained unlike Tampermonkey which has a larger proprietary ecosystem.
SourceCosign: Is signing alone enough?
No. Verification is a command somebody runs. Without an admission controller enforcing it, an unsigned image still runs.
Violentmonkey: What browsers does Violentmonkey support?
Violentmonkey works on browsers with WebExtensions support, including Chrome, Firefox, Edge, and other Chromium-based browsers.
SourceCosign: What does a bare cosign verify actually prove?
Very little. Without a pinned certificate identity and OIDC issuer, it accepts a valid signature from any identity at all.
Violentmonkey: How does Violentmonkey compare to Tampermonkey in performance?
Community benchmarks show Violentmonkey uses about 15 to 30 percent less RAM on Chrome compared to Tampermonkey when managing many open tabs.
SourceCosign: What is the risk of keyless signing?
Your OIDC provider becomes the root of trust. Compromise of that account yields genuine, verifiable signatures, so account security is the control that matters.
Violentmonkey: What is the current version of Violentmonkey?
Violentmonkey reached version 2.46.0 as of July 31, 2026, with active ongoing development and regular updates to the open-source project.
SourceCosign: Should we expect breaking changes?
Yes. Version 4 is announced to remove roughly half the flags, and a post-quantum migration is named as a further breaking change after that.
Related pages
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