Converters

YAML ↔ JSON Converter

Convert YAML configuration to JSON or serialize JSON as YAML. Check type changes, comment loss, parser errors, and examples in both directions.

Local processing

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About this tool

When to use it

Convert YAML configuration to JSON or serialize JSON as YAML. Check type changes, comment loss, parser errors, and examples in both directions.

How to use it

Choose YAML to JSON when an API expects a JSON body but your configuration is written in YAML. Choose JSON to YAML for a configuration file that benefits from readable lists and indentation. Select the direction before pasting: switching direction replaces the input with a matching example and clears the output. Convert, inspect types, then copy, share, or download the result.

Guide updated 2026-09-15. Examples checked against this implementation.

Worked examples

YAML to JSON: named settings

Input

name: demo
enabled: true

Expected output

{
  "name": "demo",
  "enabled": true
}

The boolean stays a boolean. Quote a YAML value when it must remain text rather than a parsed number or boolean.

JSON to YAML: a region list

Input

{"retries":3,"regions":["in","eu"]}

Expected output

retries: 3
regions:
  - in
  - eu

The array becomes a block list. The serializer chooses indentation and quoting, and ends the YAML document with a newline.

Errors and unsupported input

items: [

Close the sequence bracket or rewrite the values as an indented list. Check the parser location, then retry.

value: .inf

JSON cannot represent infinity or NaN. Use a quoted string or an agreed finite value; conversion rejects these numbers instead of changing them to null.

Continue this workflow

YAML ↔ TOML Converter: Convert a YAML mapping into TOML when your target application uses tables.
JSON Diff: Compare converted JSON against a known configuration to inspect type and value changes.

Format references

js-yaml parser and serializer

Format rules and limitations

Each direction accepts up to 2 MiB of input and one document at a time. This is format conversion, without validation against your application configuration schema.

Comments and original formatting are lost. YAML aliases are resolved into values; alias syntax is not preserved in JSON. Cyclic aliases cannot become JSON.

Parsed numbers use JavaScript precision. Quote exact identifiers before conversion. Custom YAML tags may be rejected; support depends on the installed parser.

JSON-to-YAML accepts arrays and primitives as well as objects. JSON comments, trailing commas, and unquoted property names are invalid.

Privacy and security

These tools process input in browser memory without an upload or processing API. DevMate does not save these inputs in localStorage, sessionStorage, or a share URL. Reloading starts a new workspace; browser history restoration may retain form state. Copy writes to your system clipboard and Download saves a file, which can outlive the tab. The page still loads site assets and may contact configured analytics, consent, or advertising services. DevMate analytics records route and action names, without input, output, filenames, or raw errors. Selecting Share sends the converted text to the app you choose through your device's share dialog; when native sharing is unavailable, it copies the text to the clipboard.

Review sensitive or production-critical output in the trusted system where it will be used.

Questions

Frequently asked questions

Will YAML comments appear in JSON?

No. Comments are not part of the converted values. Keep the original YAML when its explanations need to survive.

Does switching direction reuse the previous output?

No. It loads a matching example. Copy your result before switching, then paste it into the new input if you want to check a round trip.