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Developer Tools · head to head

Blacksmith vs Clerk

Blacksmith logo

Blacksmith

Developer Tools

2x faster GitHub Actions with 60% cost savings

From
Free
Free plan
Yes
Full reviewWebsite
Clerk logo

Clerk

Cybersecurity

Drop-in user authentication and management for developers

From
Free
Free plan
Yes
Full reviewWebsite

The short version

  • Each has a real cost: Blacksmith per-minute pricing model requires estimating usage to predict costs; Clerk pricing scales with monthly retained users, which can grow expensive quickly for consumer apps with large user bases.
  • They diverge on capability: Blacksmith covers Bare metal runners, Clerk covers Prebuilt UI components.
  • Prices and features above were last checked on 29 August 2026.

Where they differ

Only the attributes on which Blacksmith and Clerk actually diverge.

Attributes where Blacksmith and Clerk differ
AttributeBlacksmithClerk
Pricing modelUnknownfreemium
PlatformsGitHub Actions, Linux, Windows, macOSweb, ios, android, api
CategoryDeveloper ToolsCybersecurity

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 Blacksmith

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

Only in Clerk

  • Prebuilt UI components
  • Organization management
  • Multi-factor authentication
  • Social sign-on
  • Billing
  • Enterprise connections

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 Clerk
  • Accelerating CI build times for organizations with heavy CI loadnot Clerk
  • Reducing cloud spend on GitHub Actions by 60% or morenot Clerk
  • Supporting ARM architecture builds without GitHub runnersnot Clerk

Clerk

  • Adding sign-in and user profiles to a web or mobile app quicklynot Blacksmith
  • B2B SaaS apps needing organizations and role-based accessnot Blacksmith
  • Startups wanting prebuilt UI instead of building auth in-housenot Blacksmith
  • Apps needing MFA and fraud detection out of the boxnot 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

Clerk

  • Pricing scales with monthly retained users, which can grow expensive quickly for consumer apps with large user bases.
  • Enterprise SSO connections beyond the first are billed as add-ons, adding cost for larger organizations.
  • The Business tier's extra dashboard seats cost $20/month each, which adds up for larger teams.
  • Enterprise-tier features like the 99.99% uptime SLA require annual contracts rather than flexible monthly billing.

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

Clerk

Free
  • HobbyFree
    • 50,000 MRU limit per app
    • Up to 3 dashboard seats
    • Unlimited applications
  • Pro$25/month
    • 50,000 MRUs included, $0.02/MRU overage
    • Up to 3 dashboard seats
    • 1 Enterprise Connection included
  • Business$300/month
    • 50,000 MRUs included with volume pricing
    • 10 dashboard seats included
    • SOC2 report and priority support
  • Enterprise$undefined/month
    • Custom pricing, annual billing
    • 99.99% uptime SLA
    • HIPAA available, dedicated Slack channel

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 Clerk if

  • You need prebuilt ui components.
  • You want to start without paying.
  • You work on web, ios, android, api.
  • You also want organization management.
Clerk review

Questions people ask

Is Blacksmith or Clerk better?
Neither clearly leads. Blacksmith starts at Free and Clerk at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Blacksmith or Clerk?
Blacksmith starts at Free and Clerk at Free.
Does Blacksmith or Clerk run on more platforms?
Blacksmith runs on GitHub Actions, Linux, Windows, macOS. Clerk runs on web, ios, android, api.
Can I use Blacksmith for free?
Both have a free tier, so you can try either at no cost before committing.
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 Clerk is typically brought in for.
What can Blacksmith do that Clerk cannot?
Blacksmith covers Bare metal runners, Multiple OS support, ARM support, Docker layer caching. Clerk covers Prebuilt UI components, Organization management, Multi-factor authentication, Social sign-on.

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
Clerk: What does Clerk cost?

Clerk's Hobby plan is free with a 50,000 MRU limit; Pro is $25/month ($20/month billed annually), Business is $300/month ($250 annually), and Enterprise uses custom annual pricing.

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
Clerk: Is there a free plan and what are its limits?

Yes, the Hobby plan is free with a 50,000 monthly retained user (MRU) limit per app, up to 3 dashboard seats, and unlimited applications, with no credit card required.

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
Clerk: How is usage metered?

Clerk meters by monthly retained users (MRUs) — users who return to the app at least a day after signing up — with overage billed at $0.02 per MRU beyond the included 50,000 on paid plans.

Source
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