Blacksmith vs compiler.dev: Runner Price and Speed

Blacksmith and compiler.dev both run your existing GitHub Actions jobs on faster rented machines, so you keep your workflows and change one line. Blacksmith is the more established name with a larger feature set around caching and Docker builds. compiler.dev is cheaper per minute at the 2 vCPU size and falls back to your old runners automatically. Prices below were checked in October 2026 on Blacksmith's pricing page and compiler.dev pricing.

What Blacksmith is

Blacksmith is a hosted runner provider for GitHub Actions. You install its GitHub app, point runs-on at a Blacksmith label, and jobs run on its hardware. It works with GitHub organizations only, not personal repositories, according to its quickstart docs.

Three things stand out about it. First, a cache that is co-located with the runners: on Blacksmith runners, actions/cache calls use Blacksmith's own cache without workflow changes, and each repository gets 25 GB of free cache storage per week. Second, Docker layer caching through sticky disks, priced at $0.50 per GB per month. Third, it covers Linux x64, Linux ARM, Windows and macOS under one account.

Side-by-side

Blacksmith's page does not map prices to larger vCPU sizes, so we do not compare at 8 vCPU. If you plan to use large Blacksmith sizes, read its current price list before you decide. Our own runner price table lists every provider side by side.

Where Blacksmith is the better choice

• You need Windows or ARM Linux. compiler.dev runs Linux x64 and, in early access, macOS. Blacksmith covers more platforms today.
• You want the free minutes. 3,000 a month at no cost is a lot more than a 200 minute trial, and for small teams it may cover the whole bill.
• Your build is a Docker build. Sticky disks and the Docker builder replacement are built for persistent layer caches across runs. See Docker layer caching in CI for what to expect from any provider.
• You want a larger user community and ecosystem. More teams have written about running on Blacksmith, which helps when you hit an odd problem.

Where compiler.dev is the better choice

• You want a safety net. If your credit runs out or something fails, jobs run on the runners you used before. Blacksmith's public pricing page does not describe a fallback.
• You want a lower 2 vCPU rate and a simple model. $0.003 vs $0.004 per minute is a small gap, so this matters only at scale.
• You hit GitHub outages. compiler.dev tracks GitHub's status, re-delivers missed webhooks and re-runs failed jobs after recovery.
• You want measured numbers on your own jobs. compiler.dev publishes full-pipeline benchmarks where full CI runs were a median 1.5× faster across 18 measured stacks (15 faster, 2 the same, 1 slower) than GitHub-hosted, for example 6m57s down to 2m18s for an Angular, Spring Boot and Postgres project. We have not benchmarked Blacksmith, so we make no speed claim against it. Blacksmith's own pricing page claims 2x faster runs than GitHub; that is its claim, not our measurement.

How to switch

From GitHub-hosted to Blacksmith:

jobs:
  test:
    runs-on: blacksmith-4vcpu-ubuntu-2404
    steps:
      - uses: actions/checkout@v4
      - run: npm ci && npm test

From Blacksmith (or GitHub-hosted) to compiler.dev:

jobs:
  test:
    runs-on: [self-hosted, Linux, compiler-ci]
    steps:
      - uses: actions/checkout@v4
      - run: npm ci && npm test

Install the GitHub App at app.compiler.dev first. To undo, change the line back. If you are on Blacksmith's Docker builder actions, switch back to docker/setup-buildx-action and docker/build-push-action before you move, since those are Blacksmith-specific.

A fair way to decide

Per-minute price only matters together with minutes used. A job that runs 10 minutes at $0.004 costs 4 cents; if a faster machine finishes in 6 minutes at $0.012, it costs 5.4 cents but returns developers 4 minutes sooner. Use the cost calculator and the cost of slow CI calculator to put numbers on both sides, and run your real workflow on each provider for a day. Both offer a trial. Our broader provider ranking covers the other options too.

FAQ

Is Blacksmith cheaper than compiler.dev?

At 2 vCPU x64, Blacksmith is $0.004 a minute and compiler.dev is $0.003 (checked October 2026). Blacksmith gives 3,000 free minutes a month, so for light usage it can cost nothing. For larger sizes, Blacksmith's page shows no per-size prices, so compare on your own quote.

Does compiler.dev support ARM or Windows runners like Blacksmith?

No. compiler.dev offers Linux x64 and macOS in early access. If you need ARM Linux or Windows, Blacksmith is the better fit.

Can I use both at the same time?

Yes. runs-on is set per job, so you can run Docker builds on Blacksmith and unit tests on compiler.dev while you compare.

What happens to my cache if I move?

Caches are not portable between providers. The first run after switching will be a cold run, then caches fill again. See GitHub Actions caching for how keys work.

Is Blacksmith a replacement for GitHub Actions?

No. It is a runner provider. Your workflows, triggers and the Actions UI stay on GitHub, and only the machines change.