YAML Validator
Validate, format, and convert YAML to JSON with error detection and statistics. 100% free.
No sign-up
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100% free
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Private
Yaml Validator Error Details
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Path Viewer
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Yaml Validator Keys
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YAML Validator and Formatter
The YAML Validator and Formatter is a free online tool that checks your YAML syntax for errors and formats it with consistent, readable indentation. Paste your YAML content and the validator instantly identifies syntax errors — incorrect indentation, invalid characters, unclosed strings, duplicate keys, and type mismatches — with clear error messages pointing to the exact line and column where the problem occurs. The formatter then cleans up your YAML with standardized indentation and consistent formatting.The validator supports all YAML 1.2 features: mappings (key-value pairs), sequences (lists/arrays), scalars (strings, numbers, booleans, null), anchors and aliases (& and *), multi-line strings (literal | and folded > blocks), comments, and multi-document files (separated by ---). The formatter standardizes indentation to 2 spaces (configurable), removes trailing whitespace, and normalizes quoting style. The tool also provides a JSON conversion view, since YAML is a superset of JSON.DevOps engineers validate Kubernetes manifests, Docker Compose files, Ansible playbooks, and CI/CD pipeline configurations (GitHub Actions, GitLab CI). Backend developers check application configuration files (Spring Boot, Rails, Django). Cloud architects validate CloudFormation, Terraform (HCL→YAML), and Helm chart templates. Technical writers format YAML examples for documentation. A single indentation error in YAML can cause deployment failures — this tool catches them before they reach production.YAML Validator is part of the facilita.tools developer toolkit. Available in Portuguese, English, and Spanish, optimized for desktop and mobile browsers.
Frequently Asked Questions
What is YAML?
YAML (YAML Ain't Markup Language) is a human-readable data serialization format commonly used for configuration files. Unlike JSON, it uses indentation instead of braces and supports comments. It is the standard format for Kubernetes, Docker Compose, GitHub Actions, and many DevOps tools.
What are common YAML syntax errors?
The most common errors are: inconsistent indentation (mixing tabs and spaces), missing colons after keys, unquoted special characters, and duplicate keys. YAML requires spaces (not tabs) for indentation.
How do I convert YAML to JSON?
Our tool can convert YAML to JSON and vice versa. YAML and JSON are largely compatible: YAML is a superset of JSON. The main differences are that YAML uses indentation, supports comments, and has additional data types like dates and multiline strings.