DataHub Tools JSON to YAML

JSON to YAML Converter

Local-first

Convert JSON objects and arrays into readable YAML.

How this tool actually works

The tool validates input with JSON.parse and serializes the resulting JavaScript value through js-yaml using two-space indentation. It converts data values, not original JSON spelling, duplicate keys, or formatting.

  • Validate strict JSON
  • Serialize parsed values as YAML
  • Download readable YAML output

How to use it

  1. Paste strict JSON containing an object, array, or scalar.
  2. Convert and inspect strings, numbers, booleans, nulls, and nested values.
  3. Check duplicate keys and large integers against the source before relying on the YAML.
  4. Download only after validating the output against the receiving application's schema.

Quick example

Example input

{"name":"Ada","active":true,"skills":["SQL","Python"]}

Expected result

name: Ada
active: true
skills:
  - SQL
  - Python

Duplicate JSON keys are overwritten during parsing, and numbers beyond JavaScript's safe range may lose precision before YAML is generated.

Best use cases

  • Convert simple API JSON into a YAML configuration draft.
  • Inspect nested JSON as readable YAML.
  • Prepare ordinary mappings and sequences for manual review.

Official standards and scope

JSON and YAML overlap for common values but differ in syntax and data-model features. This page parses strict JSON and serializes the resulting JavaScript value, so original spelling, formatting, duplicate keys, and number precision beyond the JavaScript range are not preserved.

Sources checked July 27, 2026. Standards can change; review the original sources again before formal integration or compliance decisions.

Known limitations

  • JSON comments and original formatting do not exist after parsing.
  • YAML quoting can differ from the original JSON while preserving the parsed value.
  • Downloads use the registered application/yaml media type.

FAQ

Which parser and serializer are used?

The page uses JSON.parse followed by browser-local js-yaml.

Are duplicate keys preserved?

No. JSON.parse keeps the final value for each repeated key.

Can large integers change?

Yes. JavaScript number precision applies before YAML serialization.

Does YAML preserve the JSON layout?

No. Indentation, quoting, key spacing, and number spelling are regenerated.

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