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Cybersecurity · head to head

Mimecast vs Sigstore

Mimecast logo

Mimecast

Cybersecurity

Email and collaboration security

From
$4/month
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

  • Only Sigstore has a free tier, so it costs nothing to try first.
  • Each has a real cost: Mimecast no pricing is published for any product or plan, and every route ends at a quote or demo request; 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: Mimecast covers Advanced threat detection, Sigstore covers Fulcio.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Mimecast and Sigstore actually diverge.

Attributes where Mimecast and Sigstore differ
AttributeMimecastSigstore
Starting price$4/monthFree
Pricing modelsubscriptionOpen source, public instance free to use
Free tierNoYes
PlatformsEmail, Cloud, CollaborationWeb, Linux, macOS, Windows, Self-hosted
Founded2003Unknown

Identical on both: user rating (Not yet rated), category (Cybersecurity).

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 Mimecast

  • Advanced threat detection
  • Secure sharing
  • Email encryption
  • Message tracking
  • Email archiving
  • Legal hold
  • eDiscovery
  • Backup and recovery

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.

Mimecast

  • Email security filtering against phishing and targeted attacksnot Sigstore
  • Email archiving, continuity and compliance for organisationsnot Sigstore

Sigstore

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

Where each one falls short

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

Mimecast

  • No pricing is published for any product or plan, and every route ends at a quote or demo request
  • The platform is split into separately sold products for email security, awareness training, data protection and governance
  • Collaboration threat protection, DMARC analysis, incident response and email archiving are all further add ons on top of those

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

Mimecast

$4/month
  • Defender$4/month
    • Per user
    • Threat protection
    • Impersonation prevention
  • Archive$3/month
    • Email archiving
    • Legal hold
    • Search & recall
  • Unified$6/month
    • All Defender features
    • All Archive features
    • Backup

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 Mimecast if

  • You need advanced threat detection.
  • You work on Email, Cloud, Collaboration.
  • You also want secure sharing.
Mimecast 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 Mimecast or Sigstore better?
Neither clearly leads. Mimecast starts at $4/month and Sigstore at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Mimecast or Sigstore?
Sigstore has a free tier; the other does not. Paid plans start at $4/month for Mimecast and Free for Sigstore.
Does Mimecast or Sigstore run on more platforms?
Mimecast runs on Email, Cloud, Collaboration. Sigstore runs on Web, Linux, macOS, Windows, Self-hosted.
Can I use Sigstore for free?
Yes. Sigstore has a free tier, so you can try it without paying. Mimecast starts at $4/month.
What is Mimecast best used for?
Mimecast is most often used for email security filtering against phishing and targeted attacks, email archiving, continuity and compliance for organisations. Of those, email security filtering against phishing and targeted attacks and email archiving, continuity and compliance for organisations are not what Sigstore is typically brought in for.
What can Mimecast do that Sigstore cannot?
Mimecast covers Advanced threat detection, Secure sharing, Email encryption, Message tracking. Sigstore covers Fulcio, Rekor, Keyless signing, Multi-language clients.

Answered from the vendors’ own pages

Mimecast: How much does Mimecast cost?

Mimecast does not publish pricing on its website. Customers must request a custom quote by contacting the sales team at +1 617 393 7000 or using the Get a Quote button.

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.

Mimecast: Is there a free trial of Mimecast?

Mimecast's trial and pricing options are not specified on the public website. Contact sales at +1 617 393 7000 or through their support portal at mimecastsupport.zendesk.com for trial availability.

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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