YAML Linter
Lint YAML for syntax errors, duplicate keys, and style issues.
What is YAML Lint?
A YAML linter that combines js-yaml syntax validation with style checks developers actually hit: tabs in indentation, trailing whitespace, and duplicate keys.
How it works
The document is parsed with js-yaml (which rejects duplicate keys), then each line is scanned for tab indentation and trailing whitespace.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Catching silent config bugs
Lint a config for tabs, duplicate keys, bad indentation, and type surprises before it reaches a deployment pipeline.
Common mistakes
Duplicate keys pass silently
Many parsers keep the last duplicate key without error. The linter reports duplicates — a common source of production bugs.
Frequently asked questions
What rules are checked?
Indentation consistency, tabs, duplicate keys, trailing whitespace, and common type pitfalls.
Does it auto-fix problems?
Some issues (like trailing whitespace) are fixable in one click; structural ones are reported with positions.