YAML Validator & Syntax Checker
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YAML's reliance on whitespace makes it especially prone to subtle indentation mistakes that silently change meaning or break parsing entirely, unlike brace-delimited formats. This YAML validator parses your document and reports whether it's syntactically valid, pointing out the specific line where an indentation or structural error occurs. It's essential for DevOps engineers validating Kubernetes manifests, CI/CD configs, and Docker Compose files before deployment, where a bad YAML file can cause a pipeline to fail confusingly. The validator catches common mistakes like mixed tabs and spaces, inconsistent list indentation, and unclosed quoted strings. Since validation runs entirely in your browser, your document is never uploaded to a server, and there's no signup required. Paste your YAML below to check it instantly.
Features
- Validates YAML syntax and reports parse errors clearly
- Pinpoints the exact line of indentation or structural issues
- Detects mixed tabs and spaces, a common YAML pitfall
- Flags unclosed quoted strings and invalid scalar values
- Supports multi-document YAML files separated by ---
- Validates anchors, aliases, and block scalars
- Works with both compact and formatted YAML
- Fully client-side validation with no data upload
Why use this yaml validator?
- Finds YAML errors in seconds before a failed deployment
- Keeps configuration files private with local-only processing
- Pinpoints the exact line causing the parse failure
- No setup needed - just paste and validate
- Free with unlimited validations
Frequently asked questions
Why is YAML so prone to syntax errors?
YAML relies on whitespace and indentation to define structure instead of braces or brackets, so a single misplaced space can silently change the meaning or break parsing.
Does the validator catch mixed tabs and spaces?
Yes, mixing tabs and spaces for indentation is a common cause of YAML errors, and the validator flags it specifically.
Can it validate Kubernetes manifests or Docker Compose files?
Yes, since those are standard YAML documents, the validator checks their core syntax, though it doesn't verify Kubernetes-specific schema rules.
Does it support multi-document YAML files?
Yes, files with multiple documents separated by --- are parsed and validated individually.
Is my YAML data uploaded to validate it?
No, validation runs entirely in your browser using local JavaScript, so your document is never sent to a server.
What's a common YAML mistake this tool catches?
Inconsistent indentation of list items or mapping keys at the same nesting level is one of the most frequent errors flagged.
Can I format the YAML after fixing validation errors?
Yes, use the companion YAML Formatter to standardize indentation once your document passes validation.