Is my YAML data uploaded to a server?

No. Everything runs entirely in your browser with JavaScript. Nothing is sent over the network, which makes the tool safe for sensitive data.

Are anchors and merge keys supported?

Anchors and merge keys (<<: *base) are resolved while parsing, so the output is the expanded, canonical document — handy to see what your YAML actually contains.

Will my comments be preserved?

No. The document is parsed and re-serialized, which drops comments — the trade-off for a perfectly consistent layout.

100% local — your data never leaves your browser

YAML Formatter & Beautifier — Free Online Tool

Reformat YAML with consistent indentation and optional key sorting, in your browser. Free, private, offline-friendly: your data never leaves your device.

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Indentation

YAML input

YAML output

Why format YAML?

YAML files accumulate inconsistent indentation, flow styles and quoting as they grow. Paste your YAML above to normalize it to a clean, consistent layout in an instant.

How it works

The formatter parses your YAML locally (merge keys included) and re-serializes it with the indentation you pick. Enable Sort keys to order mappings alphabetically at every level. Invalid YAML is rejected with the parser’s line and column.

Frequently asked questions

Is my YAML data uploaded to a server?: No. Everything runs entirely in your browser with JavaScript. Nothing is sent over the network, which makes the tool safe for sensitive data.
Are anchors and merge keys supported?: Anchors and merge keys (<<: *base) are resolved while parsing, so the output is the expanded, canonical document — handy to see what your YAML actually contains.
Will my comments be preserved?: No. The document is parsed and re-serialized, which drops comments — the trade-off for a perfectly consistent layout.