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Cybersecurity · head to head

Cosign vs Unleash

Cosign logo

Cosign

Cybersecurity

Signs and verifies container images and artifacts, with or without managing keys

From
Free
Rated
-
Full reviewWebsite
Unleash logo

Unleash

Software Development

Open-source feature flag and experimentation service

From
Free
Rated
-
Full reviewWebsite

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.; Unleash the Pay-As-You-Go plan is priced per seat, which can get costly for larger teams.
  • They diverge on capability: Cosign covers Keyless signing, Unleash covers Feature flags.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Cosign and Unleash actually diverge.

Attributes where Cosign and Unleash differ
AttributeCosignUnleash
Pricing modelOpen source, no licence feefreemium
PlatformsmacOS, Linux, Windows, Dockerweb, api, linux
CategoryCybersecuritySoftware Development

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 Unleash

  • Feature flags
  • A/B/n testing
  • Custom targeting
  • SDKs
  • SSO
  • Audit logs

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 Unleash
  • Attaching a signed bill of materials to a release so consumers can verify its provenancenot Unleash
  • Meeting a customer or regulatory requirement for signed artifactsnot Unleash
  • Verifying third-party images before they enter an internal registrynot Unleash

Unleash

  • Gradual and progressive feature rolloutsnot Cosign
  • Running A/B/n experiments tied to flagsnot Cosign
  • Self-hosting feature management for compliance needsnot Cosign
  • Enterprise SSO-controlled feature flag governancenot 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.

Unleash

  • The Pay-As-You-Go plan is priced per seat, which can get costly for larger teams.
  • Self-hosted Enterprise requires a minimum of 5 seats and an annual contract.
  • Additional API traffic beyond the included quota is billed per million requests.
  • Advanced SLAs and dedicated customer success are reserved for the custom Enterprise tier.

Pricing, plan by plan

Cosign

Free
  • CosignFree
    • Apache-2.0
    • Public Sigstore infrastructure free to use
    • No usage limits published

Unleash

Free
  • Pay-As-You-Go$75/month
    • Cloud-hosted
    • 53M API requests/month included
    • Unlimited feature flags, projects and environments
  • Custom Enterprise$undefined/mo
    • Cloud, self-hosted or hybrid
    • Premium support options
    • 99.99% uptime SLA

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.
Cosign review

Choose Unleash if

  • You need feature flags.
  • You want to start without paying.
  • You work on web, api, linux.
  • You also want a/b/n testing.
Unleash review

Questions people ask

Is Cosign or Unleash better?
Neither clearly leads. Cosign starts at Free and Unleash at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cosign or Unleash?
Cosign starts at Free and Unleash at Free.
Does Cosign or Unleash run on more platforms?
Cosign runs on macOS, Linux, Windows, Docker. Unleash runs on web, api, linux.
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 Unleash is typically brought in for.
What can Cosign do that Unleash cannot?
Cosign covers Keyless signing, Key and KMS signing, Registry-native storage, In-toto attestations. Unleash covers Feature flags, A/B/n testing, Custom targeting, SDKs.

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.

Unleash: What does Unleash cost?

Unleash offers a Pay-As-You-Go cloud plan at $75/seat/month with a 14-day free trial, plus a custom-priced Enterprise plan for self-hosted or hybrid deployments.

Source
Cosign: Is signing alone enough?

No. Verification is a command somebody runs. Without an admission controller enforcing it, an unsigned image still runs.

Unleash: How is usage metered?

The Pay-As-You-Go plan includes 53M API requests per month, with additional traffic billed at $5 per million requests thereafter.

Source
Cosign: 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.

Unleash: What does Unleash integrate with, and is there an API?

Unleash provides an API and 25+ official SDKs across languages, along with SSO integrations via SAML 2.0 and OpenID Connect.

Source
Cosign: 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.

Cosign: 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.

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