YAML ⇄ JSON Converter (Round-trip validation)

Convert YAML to JSON or JSON back to YAML, including YAML 1.2 features such as anchors, aliases, and merge keys. Use the Validate buttons to check round-trip equivalence while ignoring cosmetic differences like optional double quotes.

YAML

JSON

Options

Sort keys in output (stable order) YAML: force quotes on all keys/values YAML: use flow style for shallow arrays/objects YAML: output null as empty string

Indent

How to use

Paste YAML on the left and JSON on the right, or load files into each side.
Select YAML → JSON or JSON → YAML to convert.
Use the Validate buttons to confirm round-trip equivalence.

Notes

Equivalence checks compare the parsed data structure, so differences like optional double quotes are ignored. Anchors (&ref / *ref) and merge keys (<<: *ref) are supported. Everything runs locally with the bundled js-yaml library.

YAML and JSON differ in capability, so round-tripped files may not match originals byte for byte.
Comments - YAML supports # comments, but JSON has no official comment syntax. - Comments are therefore dropped when converting to JSON.
Anchors & aliases (&name, *name) - JSON has no anchor concept, so values are expanded when converting. - Returning to YAML does not recreate the original anchor notation automatically.
Key order - JSON does not guarantee object key order, so ordering may change.
Numeric formats - Leading-zero numbers (e.g., 0123), hex values, NaN, and Infinity fall back to strings in JSON.
Other differences - Minor presentation differences such as optional quoting are expected even though the data is equivalent.

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