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Developer Tools · head to head

Blacksmith vs Mimecast

Blacksmith logo

Blacksmith

Developer Tools

2x faster GitHub Actions with 60% cost savings

From
Free
Free plan
Yes
Full reviewWebsite
Mimecast logo

Mimecast

Cybersecurity

Email and collaboration security

From
$4/month
Free plan
No
Full reviewWebsite

The short version

  • Only Blacksmith has a free tier, so it costs nothing to try first.
  • Each has a real cost: Blacksmith per-minute pricing model requires estimating usage to predict costs; Mimecast no pricing is published for any product or plan, and every route ends at a quote or demo request
  • They diverge on capability: Blacksmith covers Bare metal runners, Mimecast covers Advanced threat detection.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Blacksmith and Mimecast actually diverge.

Attributes where Blacksmith and Mimecast differ
AttributeBlacksmithMimecast
Starting priceFree$4/month
Pricing modelUnknownsubscription
Free tierYesNo
PlatformsGitHub Actions, Linux, Windows, macOSEmail, Cloud, Collaboration
CategoryDeveloper ToolsCybersecurity
FoundedUnknown2003

Identical on both: 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 Blacksmith

  • Bare metal runners
  • Multiple OS support
  • ARM support
  • Docker layer caching
  • Sticky disks
  • GitHub Actions observability
  • Free tier
  • Static IPs

Only in Mimecast

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

What people use each for

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

Blacksmith

  • Replacing GitHub Actions runners with faster, cheaper infrastructurenot Mimecast
  • Accelerating CI build times for organizations with heavy CI loadnot Mimecast
  • Reducing cloud spend on GitHub Actions by 60% or morenot Mimecast
  • Supporting ARM architecture builds without GitHub runnersnot Mimecast

Mimecast

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

Where each one falls short

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

Blacksmith

  • Per-minute pricing model requires estimating usage to predict costs
  • macOS M4 pricing ($0.08/min) is significantly higher than GitHub Actions
  • Docker layer caching and sticky disks are paid add-ons at $0.50/GB/mo
  • Static IP add-on costs $100/IP/mo

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

Pricing, plan by plan

Blacksmith

Free
  • Ubuntu x64$0.004/minute
    • 3,000 free minutes per month
    • 2x faster hardware
    • 4x faster cache downloads
  • Ubuntu ARM$0.0025/minute
    • 3,000 free minutes per month
    • 2x faster hardware
    • 4x faster cache downloads
  • Windows x64$0.008/minute
    • 3,000 free minutes per month
    • 2x faster hardware
    • 4x faster cache downloads
  • macOS M4$0.08/minute
    • 3,000 free minutes per month
    • 2x faster hardware
    • 4x faster cache downloads

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

Which should you pick?

Choose Blacksmith if

  • You need bare metal runners.
  • You want to start without paying.
  • You work on GitHub Actions, Linux, Windows, macOS.
  • You also want multiple os support.
Blacksmith review

Choose Mimecast if

  • You need advanced threat detection.
  • You work on Email, Cloud, Collaboration.
  • You also want secure sharing.
Mimecast review

Questions people ask

Is Blacksmith or Mimecast better?
Neither clearly leads. Blacksmith starts at Free and Mimecast at $4/month, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Blacksmith or Mimecast?
Blacksmith has a free tier; the other does not. Paid plans start at Free for Blacksmith and $4/month for Mimecast.
Does Blacksmith or Mimecast run on more platforms?
Blacksmith runs on GitHub Actions, Linux, Windows, macOS. Mimecast runs on Email, Cloud, Collaboration.
Can I use Blacksmith for free?
Yes. Blacksmith has a free tier, so you can try it without paying. Mimecast starts at $4/month.
What is Blacksmith best used for?
Blacksmith is most often used for replacing github actions runners with faster, cheaper infrastructure, accelerating ci build times for organizations with heavy ci load, reducing cloud spend on github actions by 60% or more, supporting arm architecture builds without github runners. Of those, replacing github actions runners with faster, cheaper infrastructure and accelerating ci build times for organizations with heavy ci load are not what Mimecast is typically brought in for.
What can Blacksmith do that Mimecast cannot?
Blacksmith covers Bare metal runners, Multiple OS support, ARM support, Docker layer caching. Mimecast covers Advanced threat detection, Secure sharing, Email encryption, Message tracking.

Answered from the vendors’ own pages

Blacksmith: How much do Blacksmith runners cost compared to GitHub Actions?

Blacksmith offers 60-75% cost savings depending on OS. Ubuntu x64 costs $0.004/min vs GitHub at $0.012/min. All plans include 3,000 free minutes monthly.

Source
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
Blacksmith: Can I use Docker layer caching with Blacksmith?

Yes, Docker layer caching is available as an add-on at $0.50/GB/mo. Managed Docker layer persistence is included with the base service.

Source
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
Blacksmith: What is the SLA for Enterprise plans?

Enterprise Blacksmith plans include a 99.9% SLA guarantee along with 24/7 priority support, dedicated Slack channels, white-glove onboarding, and CI optimization support.

Source
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