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Developer Tools · head to head

Atlantis vs Blacksmith

Atlantis logo

Atlantis

Developer Tools

Runs Terraform plan and apply from pull request comments, self-hosted and free

From
Free
Rated
-
Full reviewWebsite
Blacksmith logo

Blacksmith

Developer Tools

2x faster GitHub Actions with 60% cost savings

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Atlantis there is no company, no service level agreement and no paid support at any price, and the six maintainers are volunteers with day jobs, which some risk committees will not accept for a component holding production cloud credentials.; Blacksmith per-minute pricing model requires estimating usage to predict costs
  • They diverge on capability: Atlantis covers Pull request plans, Blacksmith covers Bare metal runners.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Atlantis and Blacksmith actually diverge.

Attributes where Atlantis and Blacksmith differ
AttributeAtlantisBlacksmith
Pricing modelOpen source, no licence feeUnknown
PlatformsLinux, Docker, Kubernetes, Self-hostedGitHub Actions, Linux, Windows, macOS

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Developer Tools).

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 Atlantis

  • Pull request plans
  • Comment driven apply
  • Workspace locking
  • Policy checking
  • Multi-platform webhooks
  • Custom workflows

Only in Blacksmith

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

What people use each for

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

Atlantis

  • Making Terraform review meaningful by putting the actual plan output in front of the approvernot Blacksmith
  • Removing local applies and the credential sprawl that comes with every engineer holding production keysnot Blacksmith
  • Getting pull request driven infrastructure without paying a per-user subscription for a hosted platformnot Blacksmith
  • Enforcing Conftest policies as a blocking check before an apply can runnot Blacksmith

Blacksmith

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

Where each one falls short

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

Atlantis

  • There is no company, no service level agreement and no paid support at any price, and the six maintainers are volunteers with day jobs, which some risk committees will not accept for a component holding production cloud credentials.
  • The security surface is inherently sharp, because it is an internet-reachable webhook endpoint that executes applies with privileged credentials, gated by pull request comment authorisation that is coarse next to a real policy engine.
  • It is stateful, holding a working directory and lock database on local disk, so high availability and horizontal scaling are awkward and you own upgrades, webhook plumbing, secret rotation and the host itself.
  • It lacks the features that distinguish the commercial alternatives, with no native drift detection, no cost estimation, no managed state interface and no policy engine beyond the Conftest integration.
  • Terragrunt and monorepo layouts are not first-class, requiring hand-written custom workflows and repository configuration that becomes a growing maintenance burden as the number of repositories increases.

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

Pricing, plan by plan

Atlantis

Free
  • AtlantisFree
    • Apache-2.0, no usage limits and no seat count
    • No commercial edition and no paid support tier
    • Community support through GitHub and the CNCF Slack channel

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

Which should you pick?

Choose Atlantis if

  • You need pull request plans.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes, Self-hosted.
  • You also want comment driven apply.
Atlantis review

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

Questions people ask

Is Atlantis or Blacksmith better?
Neither clearly leads. Atlantis starts at Free and Blacksmith at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Atlantis or Blacksmith?
Atlantis starts at Free and Blacksmith at Free.
Does Atlantis or Blacksmith run on more platforms?
Atlantis runs on Linux, Docker, Kubernetes, Self-hosted. Blacksmith runs on GitHub Actions, Linux, Windows, macOS.
Can I use Atlantis for free?
Both have a free tier, so you can try either at no cost before committing.
What is Atlantis best used for?
Atlantis is most often used for making terraform review meaningful by putting the actual plan output in front of the approver, removing local applies and the credential sprawl that comes with every engineer holding production keys, getting pull request driven infrastructure without paying a per-user subscription for a hosted platform, enforcing conftest policies as a blocking check before an apply can run. Of those, making terraform review meaningful by putting the actual plan output in front of the approver and removing local applies and the credential sprawl that comes with every engineer holding production keys are not what Blacksmith is typically brought in for.
What can Atlantis do that Blacksmith cannot?
Atlantis covers Pull request plans, Comment driven apply, Workspace locking, Policy checking. Blacksmith covers Bare metal runners, Multiple OS support, ARM support, Docker layer caching.

Answered from the vendors’ own pages

Atlantis: Is there a company behind Atlantis?

No. It runs as a series of LF Projects under the Linux Foundation and is maintained by volunteers. There is no vendor to buy support from and no service level agreement.

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
Atlantis: Is it a CNCF project?

No. It uses a channel in the CNCF Slack, which is often misread as membership, but the project sits under LF Projects rather than the CNCF.

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
Atlantis: Does it work with OpenTofu?

Yes, there is a dedicated integration guide alongside Terraform, and it also has configuration for working with hosted Terraform backends.

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
Atlantis: What does it not do that a paid platform does?

Drift detection, cost estimation, a managed state and run interface, and a real policy engine. Atlantis does pull request plan and apply well and stops there.

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