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Developer Tools · head to head

Earthly vs Kustomize

Earthly logo

Earthly

Developer Tools

Engineering guardrails for the AI era

From
Free
Rated
-
Full reviewWebsite
Kustomize logo

Kustomize

Cloud

Template-free customisation of Kubernetes YAML

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Earthly pricing model not published; requires sales contact; Kustomize no packaging or distribution story, which is exactly what Helm charts provide
  • They diverge on capability: Earthly covers Policy as code, Kustomize covers Overlay patching.
  • Prices and features above were last checked on 29 August 2026.

Where they differ

Only the attributes on which Earthly and Kustomize actually diverge.

Attributes where Earthly and Kustomize differ
AttributeEarthlyKustomize
Pricing modelNo pricing published on websiteOpen source, no licence fee
PlatformsWeb, CLIKubernetes, Linux, macOS, Windows
CategoryDeveloper ToolsCloud
Founded2020Unknown

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 Earthly

  • Policy as code
  • Multi-stage enforcement
  • AI agent governance
  • Repository-wide policies
  • Incident response automation
  • Compliance management
  • Earthfiles build tool
  • Satellites

Only in Kustomize

  • Overlay patching
  • No templating language
  • Built into kubectl
  • Generators

What people use each for

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

Earthly

  • Enforcing engineering standards across AI and human developersnot Kustomize
  • Automating incident response procedures across all repositoriesnot Kustomize
  • Embedding compliance requirements into development workflowsnot Kustomize
  • Standardizing build processes with Earthfilesnot Kustomize

Kustomize

  • Managing dev, staging and production variants of the same manifestsnot Earthly
  • Keeping manifests readable and directly applyable rather than templatednot Earthly
  • Patching third-party manifests without forking themnot Earthly

Where each one falls short

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

Earthly

  • Pricing model not published; requires sales contact
  • Earthly Lunar is a recent launch (2025) with limited track record
  • Primarily GitHub-focused; limited integration with other platforms
  • No public documentation on pricing or feature tiers

Kustomize

  • No packaging or distribution story, which is exactly what Helm charts provide
  • Deeply nested overlays become hard to follow, and reasoning about the final output requires building it
  • No release lifecycle: nothing tracks what is installed or supports rollback the way Helm does
  • Patch syntax is fiddly for anything beyond simple field replacement

Pricing, plan by plan

Earthly

Free

No published plan breakdown. See the Earthly review.

Kustomize

Free
  • KustomizeFree
    • Full functionality
    • No usage limits
    • Community support

Which should you pick?

Choose Earthly if

  • You need policy as code.
  • You want to start without paying.
  • You work on Web, CLI.
  • You also want multi-stage enforcement.
Earthly review

Choose Kustomize if

  • You need overlay patching.
  • You want to start without paying.
  • You work on Kubernetes, Linux, macOS, Windows.
  • You also want no templating language.
Kustomize review

Questions people ask

Is Earthly or Kustomize better?
Neither clearly leads. Earthly starts at Free and Kustomize at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Earthly or Kustomize?
Earthly starts at Free and Kustomize at Free.
Does Earthly or Kustomize run on more platforms?
Earthly runs on Web, CLI. Kustomize runs on Kubernetes, Linux, macOS, Windows.
Can I use Earthly for free?
Both have a free tier, so you can try either at no cost before committing.
What is Earthly best used for?
Earthly is most often used for enforcing engineering standards across ai and human developers, automating incident response procedures across all repositories, embedding compliance requirements into development workflows, standardizing build processes with earthfiles. Of those, enforcing engineering standards across ai and human developers and automating incident response procedures across all repositories are not what Kustomize is typically brought in for.
What can Earthly do that Kustomize cannot?
Earthly covers Policy as code, Multi-stage enforcement, AI agent governance, Repository-wide policies. Kustomize covers Overlay patching, No templating language, Built into kubectl, Generators.

Answered from the vendors’ own pages

Earthly: What is the difference between Earthfiles and Earthly Lunar?

Earthfiles is an open-source build tool that reached 12,000 GitHub stars and is used by companies like NVIDIA, Intel, and Databricks. Earthly Lunar is a separate governance platform launched in 2025 for enforcing standards across development workflows.

Source
Kustomize: Is Kustomize free?

Yes, open source and part of the Kubernetes project.

Earthly: How does Earthly Lunar enforce standards?

Lunar converts engineering standards, compliance requirements, and processes documented in AGENTS.md files, wikis, and incident postmortems into enforceable guardrails that apply consistently across repositories and development stages.

Source
Kustomize: Kustomize or Helm?

Kustomize patches plain YAML and keeps bases readable; Helm templates and packages applications with a release lifecycle. Many teams use both — Helm to install third-party charts, Kustomize to patch them.

Earthly: What is the pricing for Earthly Lunar?

Pricing is not published on the website. Interested customers should contact Earthly's sales team for current pricing and feature tiers.

Source
Kustomize: Do I need to install Kustomize?

No. It is built into kubectl, available through kubectl apply -k.

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