Davemi ToolsYAML Lint
Validate and format YAML instantly. Errors are highlighted with exact line and column numbers.
YAML Input
Result
How It Works
Paste Your YAML
Type or paste any YAML content — config files, CI pipelines, Kubernetes manifests, Docker Compose, etc.
Instant Validation
The linter runs as you type, showing errors with exact line and column numbers so you can fix issues fast.
Format & Preview
Click Format to normalize indentation, or toggle the JSON view to see the parsed data structure.
Frequently Asked Questions
What is YAML?+
YAML (YAML Ain't Markup Language) is a human-readable data serialization format commonly used for configuration files, CI/CD pipelines (GitHub Actions, GitLab CI), Kubernetes manifests, Docker Compose files, and more. It uses indentation to represent structure rather than braces or brackets.
What does this YAML linter check?+
This tool validates your YAML against the YAML 1.2 specification. It checks for syntax errors like incorrect indentation, invalid characters, duplicate keys, unclosed quotes, and malformed mappings or sequences. It reports the exact line and column where the error occurs.
Does this tool upload my YAML anywhere?+
No. All parsing and validation happens entirely in your browser using the js-yaml library compiled into this page. Nothing is sent to any server — your configuration files and secrets stay on your device.
What are common YAML syntax mistakes?+
The most common mistakes are: using tabs instead of spaces for indentation, forgetting to quote strings that contain special characters (like colons or hash symbols), incorrect nesting/indentation levels, and mixing up list (-) and mapping (key: value) syntax.
Can I format/beautify my YAML here?+
Yes! Click the 'Format' button to re-serialize your YAML with consistent 2-space indentation. This normalizes your file so it's easier to read and diff.
Does it support multi-document YAML?+
This tool validates single-document YAML. If your file contains multiple documents separated by '---', only the first document is parsed. For multi-document files, split them and validate each separately.
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