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Blacksmith vs CosmosDB

Blacksmith logo

Blacksmith

Developer Tools

2x faster GitHub Actions with 60% cost savings

From
Free
Free plan
Yes
Visit BlacksmithFull review
CosmosDB logo

CosmosDB

Databases

Globally distributed, multi-model database service from Azure

From
Free
Free plan
Yes
Visit CosmosDBFull review

The short version

  • Blacksmith is a GitHub Actions runner service.
  • CosmosDB is free; Blacksmith starts at $0.004/mo.
  • Only Blacksmith lists bare metal runners; only CosmosDB lists global Distribution.
  • Where Blacksmith falls short: per-minute pricing model requires estimating usage to predict costs.
  • Where CosmosDB falls short: autoscale provisioned throughput enforces a minimum of 1,000 RU/s, billed hourly whether or not the database is used.
  • Prices and features on this page were last checked on 13 November 2026.

Where they differ

Only the attributes on which Blacksmith and CosmosDB actually diverge.

Attributes where Blacksmith and CosmosDB differ
AttributeBlacksmithCosmosDB
PlatformsGitHub Actions, Linux, Windows, macOSWeb, Azure
CategoryDeveloper ToolsDatabases

Identical on both: starting price (Free), free tier (Yes).

Not yet recorded: pricing model for Blacksmith, founded for Blacksmith.

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 CosmosDB

  • Global Distribution
  • Multi-model APIs
  • Elastic Scaling
  • Five Consistency Levels
  • SLA-backed Latency
  • Automatic Indexing
  • Serverless
  • Azure Functions

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

CosmosDB

  • Running a globally distributed multi model database on Azurenot Blacksmith
  • Serving low latency reads and writes from multiple Azure regionsnot Blacksmith
  • Storing document, key value and graph data behind a managed servicenot 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

CosmosDB

  • Autoscale provisioned throughput enforces a minimum of 1,000 RU/s, billed hourly whether or not the database is used
  • Provisioned throughput is charged in every region the account is replicated to, so multi region accounts multiply the RU bill
  • Storage charges cover data, indexes and backups in each replicated region
  • Egress out of Azure and between regions is charged, though ingress is free
  • The free allowance is one account per Azure subscription, limited to 1,000 RU/s and 25 GB
  • RU/s rates vary by region and are only shown through the pricing calculator rather than a flat published rate

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

CosmosDB

Free
  • Free TierFree
    • 1000 RU/s
    • 25GB storage
    • First 12 months
  • ServerlessFree
    • Pay per request
    • Auto-scaling
    • Event-driven workloads

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 CosmosDB if

  • You need global distribution.
  • You want to start without paying.
  • You work on Web, Azure.
  • You also want multi-model apis.
CosmosDB review

Questions people ask

Is Blacksmith or CosmosDB better?
Neither clearly leads. Blacksmith starts at Free and CosmosDB at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Blacksmith or CosmosDB?
Blacksmith starts at Free and CosmosDB at Free.
Does Blacksmith or CosmosDB run on more platforms?
Blacksmith runs on GitHub Actions, Linux, Windows, macOS. CosmosDB runs on Web, Azure.
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 CosmosDB is typically brought in for.
What can Blacksmith do that CosmosDB cannot?
Blacksmith covers Bare metal runners, Multiple OS support, ARM support, Docker layer caching. CosmosDB covers Global Distribution, Multi-model APIs, Elastic Scaling, Five Consistency Levels.

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
CosmosDB: Is there a free tier for Azure Cosmos DB?

Yes, Cosmos DB offers a free tier with 1,000 RU/s of throughput and 25 GB of storage per month for the lifetime of the account, available to new accounts.

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
CosmosDB: How is Cosmos DB priced after the free tier?

Cosmos DB uses three billing models: provisioned throughput billed per request unit per second, vCore pricing for certain APIs, or serverless consumption pricing where you pay only for requests processed. Reserved capacity offers 20% discount for one year or 30% for three years.

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
CosmosDB: Can I change my pricing model after choosing one?

No. Once you select a compute pricing model and API, they cannot be changed. This choice is permanent for that database.

Source
CosmosDB: Is there a trial period for Cosmos DB beyond the free tier?

Azure offers a 30-day free trial account for all Azure services. Additionally, Azure AI customers may be eligible for a 90-day free Cosmos DB subscription through the Azure AI Advantage program.

Source
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