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Developer Tools · head to head

Blacksmith vs Bazel

Blacksmith logo

Blacksmith

Developer Tools

2x faster GitHub Actions with 60% cost savings

From
Free
Rated
-
Full reviewWebsite
Bazel logo

Bazel

Developer Tools

Multi-language build system with fast, correct incremental builds

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Blacksmith per-minute pricing model requires estimating usage to predict costs; Bazel steep learning curve for developers unfamiliar with build systems
  • They diverge on capability: Blacksmith covers Bare metal runners, Bazel covers Fast incremental builds.

Where they differ

Only the attributes on which Blacksmith and Bazel actually diverge.

Attributes where Blacksmith and Bazel differ
AttributeBlacksmithBazel
Pricing modelUnknownopen-source
PlatformsGitHub Actions, Linux, Windows, macOSWindows, macOS, Linux

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 Blacksmith

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

Only in Bazel

  • Fast incremental builds
  • Multi-language support
  • Distributed caching
  • Parallel execution
  • Dependency analysis
  • Starlark extensibility
  • Cross-platform support

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

Bazel

  • Building large monorepos with hundreds of interdependent projectsnot Blacksmith
  • Multi-language projects requiring consistent build semanticsnot Blacksmith
  • Organizations requiring reproducible builds and hermetic test executionnot Blacksmith
  • Teams implementing distributed CI with shared build artifact cachingnot 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

Bazel

  • Steep learning curve for developers unfamiliar with build systems
  • Initial setup complexity; requires BUILD files and Bazel configuration
  • Verbose error messages can be difficult to debug for new users
  • Smaller community and fewer third-party integrations vs enterprise tools

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

Bazel

Free

No published plan breakdown. See the Bazel review.

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 Bazel if

  • You need fast incremental builds.
  • You want to start without paying.
  • You work on Windows, macOS, Linux.
  • You also want multi-language support.
Bazel review

Questions people ask

Is Blacksmith or Bazel better?
Neither clearly leads. Blacksmith starts at Free and Bazel at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Blacksmith or Bazel?
Blacksmith starts at Free and Bazel at Free.
Does Blacksmith or Bazel run on more platforms?
Blacksmith runs on GitHub Actions, Linux, Windows, macOS. Bazel runs on Windows, macOS, Linux.
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 Bazel is typically brought in for.
What can Blacksmith do that Bazel cannot?
Blacksmith covers Bare metal runners, Multiple OS support, ARM support, Docker layer caching. Bazel covers Fast incremental builds, Multi-language support, Distributed caching, Parallel execution.

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
Bazel: Does Bazel support distributed builds across CI infrastructure?

Yes, Bazel supports distributed execution and remote caching, allowing build work to be distributed across multiple machines and CI agents.

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
Bazel: What languages can be built with Bazel?

Bazel has built-in support for Java, C++, Go, Python, and Android/iOS development, with additional language support available through custom rules and community extensions.

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
Bazel: Can I use Bazel for small projects or is it only for large monorepos?

While Bazel excels at handling large projects, it can be used for smaller codebases. However, the setup overhead may not be justified for very small or simple projects.

Source
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