Does this tool upload my YAML?

No. Every parse, transform, and download runs entirely in your browser using JavaScript and Web Workers. The file never leaves your device — there is no upload endpoint and no server-side processing.

Which YAML version is supported?

js-yaml's CORE_SCHEMA is used (a YAML 1.2 superset of the JSON schema). Anchors, aliases, multi-document streams, and block / flow styles all parse correctly. Custom !tag types are not registered.

Why does Sort keys reorder my comments?

YAML serializers cannot preserve comments through a parse / re-emit cycle — the AST drops them. If you need comment-preserving formatting, edit the file directly in your editor instead of using Sort keys.

What does Sort keys do to lists?

List order is preserved exactly. Only object (mapping) keys are sorted, and the sort applies recursively to every nested mapping.

Tools / YAML Formatter

YAML Formatter

Paste YAML on the left, get a formatted (or validated) result on the right. Errors include line and column.

Runs entirely in your browser

Mode:

Indent:

YAML Input

Formatted Output

YAML Input

Formatted Output

How to use YAML Formatter

Paste or drop YAML
Paste YAML text into the left pane, or click Load file to open a .yaml or .yml file from disk.
Pick a mode
Format normalises whitespace and indentation, Sort keys produces a canonical form for diffing, and Validate just reports whether the input parses.
Choose indentation
Pick two- or four-space indentation. The setting controls block-style nesting in the output.
Read the result
Parse errors appear above the panes with line and column. The Valid / Invalid badge tracks the current input.
Download or copy
Click Download .yaml to save the formatted result, or use the Copy button on the right pane.

Frequently asked questions

Does this tool upload my YAML?: No. Every parse, transform, and download runs entirely in your browser using JavaScript and Web Workers. The file never leaves your device — there is no upload endpoint and no server-side processing.
Which YAML version is supported?: js-yaml's CORE_SCHEMA is used (a YAML 1.2 superset of the JSON schema). Anchors, aliases, multi-document streams, and block / flow styles all parse correctly. Custom !tag types are not registered.
Why does Sort keys reorder my comments?: YAML serializers cannot preserve comments through a parse / re-emit cycle — the AST drops them. If you need comment-preserving formatting, edit the file directly in your editor instead of using Sort keys.
What does Sort keys do to lists?: List order is preserved exactly. Only object (mapping) keys are sorted, and the sort applies recursively to every nested mapping.

JSON Formatter

Format, minify, or validate JSON with configurable indentation and error reporting.

JSON ↔ YAML

Bidirectional live conversion between JSON and YAML.

JSON Schema Validator

Validate a JSON document against a JSON Schema with detailed error messages.

How to use YAML Formatter

Frequently asked questions

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