kube-score

kube-score is a free, MIT-licensed tool that statically analyzes Kubernetes object definitions and suggests ways to improve application security and resilience. Its checks include container limits, NetworkPolicy targeting, PodDisruptionBudget, Pod anti-affinity, probes, security context, and stable APIs. Optional checks cover matching resource requests and limits, container ports, and seccomp profile configuration.

The tool can run in CI/CD, where critical errors produce exit code 1; warnings can also be selected as the exit threshold. Output formats include human-readable text, JSON, CI, and SARIF. Tests may be ignored or enabled globally or for individual objects. Documentation demonstrates use with Helm, Kustomize, static YAML, Docker, and resources from a Kubernetes cluster. The browser demo accepts Kubernetes YAML or JSON and runs locally in the browser without sending data to a server. For local installation, prebuilt binaries are listed for macOS, Linux, and Windows, with Docker, Homebrew, and Kubernetes Krew options. The project recommends analyzing all applications in the same namespace together for best results. Building from source requires Go 1.21 or later.

kube-score provides configurable static analysis for Kubernetes definitions, with command-line, browser-demo, and CI-oriented options. Consider the namespace scope recommendation when preparing input for analysis.

kube-score suits Kubernetes users who want static checks on object definitions, including teams incorporating checks into CI/CD. The namespace-wide input recommendation is relevant when choosing what to analyze together.

kube-score is a free, MIT-licensed static analyzer for Kubernetes object definitions. It is best suited to developers and platform teams that want repeatable manifest checks in local workflows or CI/CD. The trade-off is that its strongest analysis depends on supplying all applications in the same namespace together.

Overview

kube-score reviews Kubernetes YAML or JSON before deployment and points to changes that can improve application security and resilience. Because it is open source with no paid tier, it fits teams that need an inspectable tool without procurement or subscription overhead. Its checks are opinionated but configurable, so it can support a shared baseline while allowing projects to suppress irrelevant tests.

The namespace guidance matters in practice: related applications should be analyzed together for the best result. Running it against isolated fragments can therefore produce a less complete assessment of how workloads interact. kube-score is a focused Kubernetes-definition reviewer, not a general-purpose security platform.

Key features

The built-in checks address concrete operational risks. They cover container limits, security context, container probes, stable API usage, NetworkPolicy targeting, PodDisruptionBudget configuration and Pod anti-affinity. Optional checks add matching resource requests and limits, container ports and seccomp profile configuration. This combination makes it useful for catching omissions that can affect scheduling, availability and workload isolation.

Configuration is practical for teams with different policies: tests can be ignored globally or per object, while optional tests can be enabled at either scope. That flexibility avoids forcing every repository to adopt an identical rule set, though it also puts responsibility on maintainers to govern which checks are disabled.

Workflow support is broad for a command-line analyzer. Documentation demonstrates use with Helm, Kustomize, static YAML files, Docker and resources retrieved from an existing Kubernetes cluster. In CI/CD, critical errors return exit code 1, and warnings can be selected as the failure threshold. Human-readable, JSON, CI and SARIF output serve interactive review, automation and reporting; SARIF is intended to ease connection with CI platforms.

The browser demo accepts Kubernetes YAML or JSON and runs entirely in the browser, according to the maker, without sending data to a server. That is a useful way to inspect a manifest without setting up an installation, particularly when source confidentiality matters. For repeatable development and pipelines, the project also offers prebuilt binaries and package-based installation.

Pricing

There is no free-trial period because the tool is free rather than trial-based. The open-source plan is the natural choice for individual engineers, small teams and organizations that can operate a command-line utility themselves. It provides the full project without seat charges or a stated usage quota, while users who require a vendor-managed service or broader security coverage should look elsewhere.

Platforms

kube-score supports Linux, macOS, Windows, self-hosted environments and the web browser demo. Prebuilt binaries are listed for macOS, Linux and Windows, and installation is also available through Docker, Homebrew and Kubernetes Krew. Building from source requires Go 1.21 or later, so package installation or binaries are the simpler route for users who do not maintain a Go toolchain.

Who it's for

Choose kube-score if you maintain Kubernetes manifests and want security- and resilience-oriented checks embedded in pull requests or deployment pipelines. It is particularly suitable for teams already using Helm, Kustomize, Docker or cluster-derived resources, and for organizations that value an MIT license and self-hosted operation.

It is less suitable when you need centralized, continuously managed posture management, an extensive multi-cloud inventory or a commercial support relationship. The namespace-wide input recommendation also means teams must organize analysis around complete application groups rather than casually scanning one object at a time.

Pros and cons

• Pro: The MIT license and zero-cost plan remove purchase barriers and permit self-hosted use.
• Pro: Checks span limits, probes, security context, networking and availability controls, with optional tests for deeper policy coverage.
• Pro: Exit-code behavior and SARIF output make the tool practical in automated CI/CD gates.
• Pro: Browser-only analysis keeps submitted YAML or JSON in the browser rather than sending it to a server, according to the maker.
• Con: Results are strongest only when all applications in the same namespace are included, complicating partial-manifest reviews.
• Con: As a static analyzer, it does not replace a broader managed security or cloud-posture service.

Alternatives

Aikido CSPM is the better choice for teams wanting a freemium, multi-platform posture-management product with a free Developer plan for two users and bounded repository, image, domain and cloud-account allowances.

Conftest suits users who want a free, Apache-licensed policy-testing tool for Linux, macOS and Windows.

Fairwinds Polaris is a free, open-source policy engine aimed at small teams across self-hosted and web workflows.

Snyk Open Source fits teams seeking freemium software-composition analysis, with a free plan capped at five projects and paid Team access.

Trivy is a free Apache-2.0 scanner for users who need a broader scanning utility across Linux and self-hosted environments.

audytx is a freemium web and API option with a paid Plus plan for unlimited repositories, files and users and 200 scans per month.

cfn-nag is a free MIT-licensed choice for Linux, macOS and self-hosted use.

Checkov is a free Apache-2.0 open-source CLI for Linux and macOS.

For broader comparisons, see Infrastructure as Code Security Software and Infrastructure Testing Tools.

Verdict

kube-score is a strong choice for Kubernetes teams that want configurable, CI-friendly static checks at no cost, especially when an MIT license and self-hosting matter. Choose it for focused manifest quality and resilience review; look elsewhere if you need managed, cross-environment posture monitoring or cannot provide complete namespace-level input.