Private developer tool

Convert JSON and YAML without uploading data

Transform one strict JSON-compatible document and keep every character in this browser.

No network access

Choose direction and paste a document

One document, up to 500,000 characters. Duplicate keys and ambiguous YAML features are rejected.

Choose indentation and convert

Conversion preserves JSON-compatible data, not YAML comments, anchors, tags, scalar styles or semantic validity for a destination system. Diff and parse the result with the authoritative target tool.