Softwr

Cybersecurity · head to head

Cosign vs Pulumi

Cosign logo

Cosign

Cybersecurity

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

From
Free
Rated
-
Full reviewWebsite
Pulumi logo

Pulumi

Cloud

Modern infrastructure as code using programming languages

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.; Pulumi the free Individual plan allows one user and one concurrent stack update
  • They diverge on capability: Cosign covers Keyless signing, Pulumi covers Multi-language support.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Cosign and Pulumi actually diverge.

Attributes where Cosign and Pulumi differ
AttributeCosignPulumi
Pricing modelOpen source, no licence feesubscription
PlatformsmacOS, Linux, Windows, DockerLinux, Windows, Mac, Api
CategoryCybersecurityCloud
FoundedUnknown2017

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 Pulumi

  • Multi-language support
  • Multi-cloud
  • State management
  • Secrets management
  • RBAC
  • Stacks
  • Automation API
  • Policy as Code

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

Pulumi

  • Infrastructure as codenot Cosign
  • Cloud resource provisioningnot Cosign
  • DevOps automationnot Cosign
  • Multi-cloud managementnot 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.

Pulumi

  • The free Individual plan allows one user and one concurrent stack update
  • The Team plan is $40 per month base including 40 credits, and caps the organisation at 10 users
  • SAML/SSO, RBAC, audit logs and drift detection require the Enterprise plan at $400 per month base
  • The per-resource rate rises from $0.1825 per resource per month on Team to $0.365 on Enterprise, so upgrading raises the unit price as well as the base fee
  • Managed secrets are billed separately at $0.50 per secret per month on Team and $0.75 on Enterprise
  • Self-hosting, SCIM user sync, audit log export and 24x7 support are only in Business Critical, which is custom priced with no published rate
  • Team includes up to 500 resources and Enterprise up to 2,000, with everything beyond billed on demand as credits

Pricing, plan by plan

Cosign

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

Pulumi

Free
  • IndividualFree
    • 1 user
    • Unlimited projects/stacks
    • 500 workflow minutes monthly
  • Team$40/month
    • Up to 10 users
    • Secure collaboration
    • CI/CD integration
  • Enterprise$400/month
    • Unlimited users
    • SAML/SSO
    • RBAC
  • Business Critical$null/custom
    • Self-hosting
    • Advanced compliance
    • SCIM integration

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 Pulumi if

  • You need multi-language support.
  • You want to start without paying.
  • You work on Linux, Windows, Mac, Api.
  • You also want multi-cloud.
Pulumi review

Questions people ask

Is Cosign or Pulumi better?
Neither clearly leads. Cosign starts at Free and Pulumi at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cosign or Pulumi?
Cosign starts at Free and Pulumi at Free.
Does Cosign or Pulumi run on more platforms?
Cosign runs on macOS, Linux, Windows, Docker. Pulumi runs on Linux, Windows, Mac, Api.
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 Pulumi is typically brought in for.
What can Cosign do that Pulumi cannot?
Cosign covers Keyless signing, Key and KMS signing, Registry-native storage, In-toto attestations. Pulumi covers Multi-language support, Multi-cloud, State management, Secrets management.

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.

Pulumi: How much does Pulumi cost?

Pulumi offers a free Individual tier forever, Team plan at $40/month with 40 credits, and Enterprise at $400/month with 400 credits. Credit usage varies by resource type and workflow needs.

Source
Cosign: Is signing alone enough?

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

Pulumi: What is included in the Pulumi free tier?

The free Individual tier includes 1 user, unlimited projects/stacks, 500 workflow minutes monthly, and 5 million Neo tokens free.

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.

Pulumi: How are Pulumi credits charged?

1 Pulumi Credit equals $1 USD. Credits are drawn from a shared pool. IaC resources cost $0.1825/month per resource on Team and $0.365 on Enterprise; ESC secrets cost $0.50-$0.75/month; workflow minutes cost $0.01 each.

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.

Pulumi: Does Pulumi offer volume discounts?

Yes, the Enterprise tier ($400/month) includes volume discounts and is designed for approximately 2,000 IaC resources.

Source
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.

Share

Related pages

More on Cosign

More on Pulumi

Keep looking

Other head to heads