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Cloud · head to head

Crossplane vs Sigstore

Crossplane logo

Crossplane

Cloud

The Cloud-Native Framework for Platform Engineering

From
Free
Rated
-
Full reviewWebsite
Sigstore logo

Sigstore

Cybersecurity

Free public signing and transparency infrastructure for open source artifacts

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Crossplane requires Kubernetes expertise and infrastructure; 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.
  • They diverge on capability: Crossplane covers Kubernetes extension, Sigstore covers Fulcio.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Crossplane and Sigstore actually diverge.

Attributes where Crossplane and Sigstore differ
AttributeCrossplaneSigstore
Pricing modelUnknownOpen source, public instance free to use
PlatformsKubernetes, AWS, Azure, GCPWeb, Linux, macOS, Windows, Self-hosted
CategoryCloudCybersecurity

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 Crossplane

  • Kubernetes extension
  • Custom API building
  • Resource management anywhere
  • Declarative interfaces
  • Component library
  • Provider ecosystem

Only in Sigstore

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

What people use each for

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

Crossplane

  • Building platform-as-a-service offerings for internal teamsnot Sigstore
  • Creating unified control layers for multi-cloud infrastructurenot Sigstore
  • Designing declarative APIs for infrastructure provisioningnot Sigstore

Sigstore

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

Where each one falls short

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

Crossplane

  • Requires Kubernetes expertise and infrastructure
  • Steep learning curve for teams new to Kubernetes patterns
  • Provider ecosystem smaller than Terraform

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.

Pricing, plan by plan

Crossplane

Free

No published plan breakdown. See the Crossplane review.

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

Which should you pick?

Choose Crossplane if

  • You need kubernetes extension.
  • You want to start without paying.
  • You work on Kubernetes, AWS, Azure, GCP.
  • You also want custom api building.
Crossplane review

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

Questions people ask

Is Crossplane or Sigstore better?
Neither clearly leads. Crossplane starts at Free and Sigstore at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Crossplane or Sigstore?
Crossplane starts at Free and Sigstore at Free.
Does Crossplane or Sigstore run on more platforms?
Crossplane runs on Kubernetes, AWS, Azure, GCP. Sigstore runs on Web, Linux, macOS, Windows, Self-hosted.
Can I use Crossplane for free?
Both have a free tier, so you can try either at no cost before committing.
What is Crossplane best used for?
Crossplane is most often used for building platform-as-a-service offerings for internal teams, creating unified control layers for multi-cloud infrastructure, designing declarative apis for infrastructure provisioning. Of those, building platform-as-a-service offerings for internal teams and creating unified control layers for multi-cloud infrastructure are not what Sigstore is typically brought in for.
What can Crossplane do that Sigstore cannot?
Crossplane covers Kubernetes extension, Custom API building, Resource management anywhere, Declarative interfaces. Sigstore covers Fulcio, Rekor, Keyless signing, Multi-language clients.

Answered from the vendors’ own pages

Crossplane: Is Crossplane free?

Yes, Crossplane is open source and free to use. It requires a Kubernetes cluster but has no licensing costs.

Source
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.

Crossplane: What is Crossplane used for?

Crossplane is used to build control planes and platforms for infrastructure management, enabling platform teams to expose safe APIs to other teams.

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.

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.

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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