Free Developer Tool — 100% Client-Side

Kubernetes YAML Validator

Name: Kubernetes YAML Validator - WebUtil
Author: WebUtil

Validate Kubernetes YAML manifests — check pods, deployments, services, and more for correct structure and required fields.

Kubernetes YAML Manifest

Validation Results

What Is a Kubernetes YAML Validator?

A Kubernetes YAML validator checks the structure and required fields of Kubernetes manifest files before you apply them to a cluster. K8s manifests define the desired state of pods, deployments, services, and other resources. Missing fields like apiVersion, kind, or metadata.name cause apply failures. Our K8s YAML linter catches these issues instantly in your browser.

Common Kubernetes Resource Validations

Deployment

Requires spec.replicas, spec.selector.matchLabels, spec.template.metadata.labels, and spec.template.spec.containers.

Service

Requires spec.ports and spec.selector to route traffic to pods.

Pod

Requires spec.containers with at least one container definition.

ConfigMap / Secret

Requires data (ConfigMap) or data/stringData (Secret).

How to Use This K8s Validator

Paste your Kubernetes YAML manifest into the textarea and click Validate. The tool parses the YAML and checks each resource against Kubernetes schema rules. Valid fields show a green checkmark, while missing or invalid fields show a red cross with an explanation. Use Load Example to see a sample Deployment manifest, and Clear to reset. All processing is client-side — your manifests never leave your device.

Tips for Valid K8s Manifests

Always set apiVersion — Use the correct version for the resource type (e.g., apps/v1 for Deployment, v1 for Pod).
Use valid kinds — Common kinds include Pod, Deployment, Service, ConfigMap, Secret, Ingress, PersistentVolumeClaim, Namespace.
Match labels correctly — spec.selector.matchLabels must match spec.template.metadata.labels for Deployments.
Container images should be explicit — Always specify the image tag, not just the image name (e.g., nginx:1.25 not nginx).
Validate before apply — Use --dry-run=client or this validator to catch errors before reaching the cluster.

Kubernetes YAML manifests define desired state configurations for containers, pods, deployments, services, ingress controllers, configmaps, and secrets across cloud-native clusters. Because YAML relies strictly on whitespace indentation and lacks runtime type safety, small syntax errors—such as using tabs instead of spaces, misaligned key blocks, invalid API versions, or missing required fields—frequently cause deployment failures during `kubectl apply` in CI/CD pipelines. Catching configuration bugs before committing code saves cluster downtime and prevents pipeline rollbacks. Every valid Kubernetes manifest requires four core top-level fields: `apiVersion` (specifying the Kubernetes API endpoint group), `kind` (the resource type, e.g. Deployment, Service), `metadata` (including name, namespace, and labels), and `spec` (the desired state specification). In addition, security best practices require declaring resource requests and limits, readiness and liveness probes, and non-root security contexts to prevent container escape and cluster starvation. WebUtil's Kubernetes YAML Validator parses manifests against official K8s schema structures, validates syntax and indentation, and checks for required fields entirely in your browser with zero file upload.

How to Do This in Code

kubectl apply --dry-run=client -f manifest.yaml
kubectl explain pod
kubectl create deployment test --image=nginx --dry-run=client -o yaml

const yaml = require('js-yaml');
const fs = require('fs');
const doc = yaml.load(fs.readFileSync('pod.yaml', 'utf8'));
console.log(doc.apiVersion, doc.kind);

import yaml
with open('deployment.yaml') as f:
    data = yaml.safe_load(f)
print(data['apiVersion'], data['kind'])

import ("os"; "sigs.k8s.io/yaml")

data, _ := os.ReadFile("deploy.yaml")
out, _ := yaml.YAMLToJSON(data)
fmt.Println(string(out))

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Related Guides & Tutorials

Web 9 min read

Kubernetes YAML: Writing Production-Grade Manifests

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Kubernetes YAML Validator FAQ

What required top-level fields must every Kubernetes manifest contain?

Every valid Kubernetes manifest must define: apiVersion (e.g. apps/v1), kind (e.g. Deployment), metadata (with at least a name), and spec (describing the desired resource state).

What are the most common Kubernetes YAML syntax mistakes?

The most frequent mistakes are: 1) Using tabs instead of spaces, 2) Inconsistent indentation on list items (-), 3) Missing required fields like selector.matchLabels, and 4) Mismatched port names.

How does client-side validation prevent cluster deployment failures?

Validating manifests before running kubectl apply or pushing to CI/CD pipelines catches syntax errors and malformed specs before they can trigger failed rollout deployments in production.

What is the difference between apiVersion 'apps/v1' and 'v1'?

Core resources like Pods, Services, and ConfigMaps belong to the core API group 'v1'. Workload controllers like Deployments, DaemonSets, and StatefulSets belong to 'apps/v1'.

Are my Kubernetes secrets and manifests safe in this validator?

Yes. All validation runs client-side in your browser's JavaScript sandbox. No manifests, secret tokens, or configurations are ever sent to an external server.