A simple object
Paste a small example into the tool and change one part at a time.
Converts to two clean YAML lines - name: Coddy and free: true.
JSON→YAML変換
JSONとYAMLを相互変換、即時バリデーション付き。
最終更新
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What is a JSON to YAML converter?
JSON and YAML are two ways of writing the same structured data - objects, arrays, strings, numbers, and booleans. JSON uses braces and brackets and is what most APIs speak; YAML uses indentation and is the go-to for configuration files (Docker Compose, Kubernetes, GitHub Actions, CI pipelines). A JSON to YAML converter translates losslessly between the two.
This tool goes both ways. In JSON → YAML mode it parses your JSON and re-emits it as indented YAML. In YAML → JSON mode it parses YAML and pretty-prints the equivalent JSON. If your input has a syntax error, you get the parser's exact message instead of a silent failure.
Everything runs locally in your browser - your configuration data, secrets, and payloads are never uploaded to a server.
What you'll learn while converting
- JSON and YAML represent the same data model - every valid JSON document is also valid YAML.
- YAML uses indentation for nesting instead of braces, which makes deep config trees easier to read.
- YAML strings usually don't need quotes, but values like
yes,no, and12:30may be interpreted specially - quote them when in doubt.
How to convert JSON to YAML step by step
Pick a direction
Choose JSON → YAML to convert JSON into YAML, or YAML → JSON for the reverse.
Paste your data
Drop your JSON or YAML into the left panel. Conversion happens instantly as you type.
Fix any errors
If the input is malformed, the right panel shows the exact parser error and line so you can fix it fast.
Copy or swap
Copy the result with one click, or hit swap to convert it straight back the other way.
Examples to try
An array
Copy the original value, run the tool, then compare the result.
Arrays become YAML lists with - bullets under the key.
Common mistakes
- Mixing tabs and spaces in YAML - YAML requires spaces for indentation; tabs cause parse errors.
- Trailing commas in JSON - valid in JavaScript objects but not in strict JSON, so they break the parser.
- Assuming comments survive a round-trip - converting YAML → JSON → YAML drops any
#comments, since JSON has none.
JSON to YAML FAQ
How do I convert JSON to YAML?
Paste your JSON into the left panel in JSON → YAML mode. The equivalent YAML appears instantly on the right, ready to copy.
Can I convert YAML back to JSON?
Yes. Switch to YAML → JSON mode and paste your YAML; the tool outputs pretty-printed JSON.
Is my data uploaded anywhere?
No. Parsing and conversion run entirely in your browser, so your config data and secrets never leave your machine.
Why did my YAML comments disappear?
JSON has no concept of comments, so any
# comments are dropped when you convert YAML to JSON and back.