YAML Validator & Formatter
Instantly validate and format YAML. Catches indentation errors, invalid syntax, and duplicate keys with exact line numbers. Free, no login.
DevOps YAML Validator
Supports: Kubernetes Deployment/Service · Docker Compose · GitHub Actions · GitLab CI
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5 Supported schemas
YAML schema validation with auto-detection that identifies your YAML format from content patterns.
| Schema | Version | Auto-detection |
|---|---|---|
| Kubernetes Deployment | v1.29 | apiVersion + kind: Deployment |
| Kubernetes Service | v1.29 | apiVersion + kind: Service |
| Docker Compose | v2.29 | services field |
| GitHub Actions | workflow | on + jobs fields |
| GitLab CI | latest | stages array |
Frequently Asked Questions
What is a YAML validator?
A YAML validator checks your YAML document for syntax errors such as incorrect indentation, invalid characters, duplicate keys, and structural issues — giving you exact line numbers and error messages.
Why is my YAML invalid?
Common YAML errors include: inconsistent indentation (mixing tabs and spaces), missing colons after keys, unquoted special characters like colons or hash signs in values, duplicate keys, and incorrect list formatting.
Can I use this to validate Kubernetes YAML?
Yes — this tool validates any YAML including Kubernetes manifests, Docker Compose files, GitHub Actions workflows, Helm values files, Ansible playbooks, and more.
Does YAML allow tabs for indentation?
No — YAML does not allow tabs for indentation. You must use spaces only. This is one of the most common causes of YAML validation errors.
Learn Kubernetes & Terraform: Step by Step
YAML is the backbone of Kubernetes and Terraform. Start our free tutorials to put your validated YAML to work.