Earthly Lunar is a guardrails platform that monitors software development activity and applies engineering policies across developer and AI workflows. It gathers structured metadata from source repositories and CI/CD pipelines, then evaluates it against policies an organization defines. Lunar can be added to existing pipelines without YAML changes or wholesale rewrites. Guardrails can operate during code authoring, on pull requests, and at deployment gates, with enforcement ranging from draft and scoring to comments or blocking changes. The platform includes more than 200 prebuilt guardrails for testing, security, compliance, and operational readiness. Its integrations page lists 66 integrations, and teams can build custom collectors and catalogers with Bash scripts. Documentation lists a SQL API for querying engineering data and a CI agent compatible with major CI vendors, including self-hosted runners. Earthly also maintains Earthfiles, an open-source syntax for portable builds. Earthly says its services and databases are hosted on AWS in the United States, encrypted at rest and in transit, and that it has SOC 2 Type II compliance.
Who it is for
Lunar suits engineering organizations that want to define and enforce development policies across repositories and CI/CD workflows. It may also suit teams using AI coding tools, which the product says it works with.
What is good
- More than 200 prebuilt guardrails are included.
- Pipeline instrumentation needs no YAML changes.
- 66 integrations are listed.
- Custom collectors can use Bash scripts.
- Supports enforcement on pull requests and deployments.
What to know first
- Services and databases are hosted in the United States.
- Custom integrations require Bash scripts.
Freedom251 review
Earthly: the full review
Earthly Lunar focuses on applying organization-defined engineering policies across the development lifecycle. Its prebuilt guardrails, integrations, and staged enforcement options are relevant for teams seeking controls without rewriting CI pipelines.
Overview
Earthly Lunar is an engineering-policy platform for teams that want to apply shared standards across repositories, CI/CD, and AI-assisted development. Its strongest fit is an organization seeking a gradual route from visibility to enforceable controls; it is not primarily a replacement for a container build system.
Earthly also maintains Earthfiles, its open-source build syntax, but its current product focus is Lunar. Earthly was founded in 2020, and Lunar launched in 2026.
Key features
Policies from authoring through deployment
Lunar collects structured metadata from source repositories and CI/CD pipelines, then checks it against organization-defined policies. Guardrails can run during code authoring, on pull requests, and at deployment gates. They can begin in draft or scoring mode and progress to PR comments, blocking pull requests, or blocking deployments. That staged approach helps teams introduce standards without making every new rule an immediate release blocker; the trade-off is that teams must define the policies they want to enforce.
Existing pipelines and broad integrations
Lunar is designed to instrument existing CI/CD pipelines without YAML changes or wholesale pipeline rewrites. Its integrations page lists 66 integrations, including collectors and catalogers, and custom collectors and catalogers can be built with Bash scripts to connect tools or APIs. The CI agent can run on self-hosted runners by adding it to the runner entrypoint, and Earthly says it is compatible with all major CI vendors. This flexibility should suit mixed toolchains, though teams with specialized systems may need to build their own connections.
Prebuilt guardrails and AI workflows
More than 200 prebuilt guardrails cover testing, security, compliance, and operational readiness. Lunar also works with Claude Code, Cursor, Codex, and pull requests, bringing its policy focus into AI-assisted workflows as well as conventional review. A SQL API lets teams query and analyze engineering data.
Security and data hosting
Earthly says it has achieved SOC 2 Type II compliance and undergoes independent third-party security assessments. Its services and databases are hosted on AWS, with databases located in the United States; databases are encrypted at rest, and applications encrypt data in transit using TLS/SSL. Teams with specific hosting or residency requirements should weigh the U.S.-located databases against their own constraints.
Earthfiles remains a separate build option
Earthfiles is an open-source syntax for self-contained, consistent, portable, language-agnostic builds, including across monorepos and polyrepos. It remains available and actively used while Earthly focuses on Lunar. Its local-daemon build method, multi-architecture builds, multiple build-cache backends, and build-secret handling make it relevant to build workflows, but those capabilities should not be confused with Lunar's policy-enforcement purpose.
Pricing
Earthly's pricing model is free, and a free plan is available. The published plan information does not provide a price beyond that free-plan designation, nor seat, quota, or trial terms to weigh. The free offering makes Lunar worth considering for teams wanting to assess policy enforcement without a stated upfront charge, but buyers should establish whether its limits and commercial terms fit their intended rollout.
Platforms
Earthly lists API, Linux, macOS, self-hosted, web, and Windows support. The self-hosted runner option is particularly relevant to teams that want CI instrumentation on their own runners rather than changing their pipeline structure.
Who it's for
Lunar is best suited to engineering organizations that need common standards across repositories and development stages, especially those adopting AI coding tools or seeking to move from advisory checks toward blocking controls. Teams that want to preserve existing CI/CD pipelines may value its instrumentation approach. It is a weaker fit for buyers primarily seeking a build system, or for organizations that need policy rules to be supplied on their behalf rather than defined internally.
Pros and cons
Pros
- More than 200 prebuilt guardrails span testing, security, compliance, and operational readiness, giving teams a substantial starting point.
- Draft, scoring, commenting, and blocking stages allow organizations to tighten enforcement over time instead of making every rule a gate from day one.
- Pipeline instrumentation without YAML changes, plus 66 listed integrations and Bash-based custom collectors, accommodates varied toolchains.
- AI coding tools are included alongside pull-request workflows, extending policy checks into AI-assisted development.
Cons
- Organizations define the policies themselves, so the platform still depends on teams to establish and maintain their standards.
- Specialized integrations may require custom Bash collectors or catalogers, adding work for teams whose tools are not covered.
- U.S.-located databases may not suit organizations with other data-residency requirements.
- Lunar is a guardrails platform, not a substitute for a build-focused tool such as Earthfiles or the alternatives below.
Alternatives
BuildKit is a free, Apache-licensed option for readers seeking a build-focused tool rather than Lunar's policy enforcement. Dagger is worth comparing for users who want a free individual tier with 1 user, 1,000,000 monthly events, one month of run history, and community support, or a paid Team plan at 50.00 US.
Garden offers a free tier with limited build minutes, cache hits, and cache retention, while its Enterprise plan includes secrets management, RBAC, and self-hosting. Readers considering another open-source build option can compare werf. Cloud Native Buildpacks Pack provides a free CLI and Go library with no paid plans listed, and Kaniko builds container images from Dockerfiles and is distributed as container images.
Google Cloud Build suits readers comparing a cloud build service with a free allowance of 2,500 build-minutes per billing account each month, then billing at $0.006 per build-minute on the stated default pool. Docker Buildx is another free build-focused alternative. For broader comparisons, see Container Build Tools and Game Build Automation Software.
Verdict
Choose Earthly Lunar if your engineering organization wants to apply its own standards across repositories, CI/CD, pull requests, and AI coding workflows, with room to strengthen controls gradually. Its combination of prebuilt guardrails and pipeline instrumentation is the main reason to choose it. Look elsewhere if your priority is building container images or managing builds rather than enforcing engineering policies.
Compared on game build automation software
- Free plan
- Yes
- Build method
- local_daemon
- Multi-architecture builds
- Yes
- Build cache backends
- multiple
- Build secret handling
- Yes





