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Cybersecurity · head to head

Sigstore vs Unleash

Sigstore logo

Sigstore

Cybersecurity

Free public signing and transparency infrastructure for open source artifacts

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

Where they differ

Only the attributes on which Sigstore and Unleash actually diverge.

Attributes where Sigstore and Unleash differ
AttributeSigstoreUnleash
Pricing modelOpen source, public instance free to usefreemium
PlatformsWeb, Linux, macOS, Windows, Self-hostedweb, 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 Sigstore

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

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.

Sigstore

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

Unleash

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

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

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

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 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 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 Sigstore or Unleash better?
Neither clearly leads. Sigstore 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, Sigstore or Unleash?
Sigstore starts at Free and Unleash at Free.
Does Sigstore or Unleash run on more platforms?
Sigstore runs on Web, Linux, macOS, Windows, Self-hosted. Unleash runs on web, api, linux.
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 Unleash is typically brought in for.
What can Sigstore do that Unleash cannot?
Sigstore covers Fulcio, Rekor, Keyless signing, Multi-language clients. Unleash covers Feature flags, A/B/n testing, Custom targeting, SDKs.

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.

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
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.

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
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.

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
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.

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.

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