Why is there no Tabs option?

YAML structure is indented with spaces. Tabs can make indentation invalid or ambiguous.

Does sorting reorder sequences?

No. Mapping keys are sorted recursively, while sequence items keep their original order.

Will formatting remove comments or anchors?

The document model preserves comments, anchors, aliases, merge keys, block scalars and markers where supported.

How are invalid aliases handled?

An alias with no available anchor is reported as an error rather than silently rewritten.

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YAML Formatter & Validator

Refine YAML configuration with space-aware formatting, structural key sorting and a tree that keeps advanced YAML features visible.

YAML Input

Drop a .yaml or .yml file onto the editor, or paste YAML directly. Tab inserts spaces using the selected indentation.

Enter or upload YAML to view the result.

Your YAML is processed locally in your browser and is not uploaded.

How to use YAML Formatter & Validator

1
Paste YAML, upload a .yaml or .yml file, or load the sample.
2
Choose two- or four-space indentation.
3
Click Format or Sort Keys and use the highlighted location if parsing fails.
4
Compare syntax-highlighted output with the mapping and sequence Tree.
5
Copy the processed YAML or download a .yaml file.

Frequently asked questions

About YAML Formatter & Validator

YAML carries presentation details that disappear in a JSON round trip, including comments, anchors and scalar styles. This formatter operates on YAML nodes directly, normalizing spacing or alphabetizing mappings while keeping sequence order and supported annotations.

Validation points to the first reliable source location. Tree view distinguishes mappings, sequences, scalars and aliases without replacing the actual text. Multi-document streams and downloads remain browser based.