YAML Formatter
Format, beautify, and validate YAML data. Free online YAML formatter and validator with error reporting. No sign-up required.
Frequently Asked Questions
What is YAML formatting?
YAML formatting (beautification) normalizes indentation, cleans up inconsistent spacing, and ensures proper structure in YAML files. Since YAML is whitespace-sensitive, consistent indentation is critical for validity.
How does the formatter work?
The formatter parses your YAML into a JavaScript object, then re-serializes it back to YAML with consistent indentation. This normalizes any irregular spacing, removes redundant blank lines, and ensures a clean, readable output.
How do I validate YAML?
Paste your YAML into the input field and click "Validate." If your YAML is well-formed, you'll see a green "Valid YAML" message. If there are errors, the tool will show the error message to help you fix it.
What are common YAML errors?
Common YAML errors include: inconsistent indentation (mixing tabs and spaces), missing colons after keys, unquoted strings with special characters, incorrect list formatting (dashes must be at the same indent level), and tabs instead of spaces (YAML does not allow tabs for indentation).
Does this tool support comments and multi-line strings?
The formatter parses YAML into structured data and re-serializes it, which means comments (#) in the original YAML will not be preserved in the output. This is a trade-off for guaranteed consistent formatting. Multi-line strings using block scalars (| and >) are supported.
Is this tool free and private?
Yes, completely free with no sign-up required. All formatting and validation happens in your browser. Your YAML data never leaves your device.