JSON to YAML Converter
Updated Free mock REST & WebSocket APIs
Paste JSON to get clean, idiomatic YAML for configs, Helm values, CI workflows or OpenAPI files. Strings that some YAML parsers would misread as booleans or dates are quoted automatically.
🔒 Runs in your browser — nothing you paste is uploaded.
How to convert JSON to YAML
- Paste JSON or drop a .json file. Errors are shown with their line and column.
- Pick the indentation and, if you like, sort keys or quote every string.
- Copy the YAML or download it as a .yaml file.
The “Norway problem”: why some strings get quoted
YAML 1.1 — still used by PyYAML, older Go libraries and plenty of tooling — reads yes, no, on, off, y and n as booleans, and 2026-10-18 as a date. So a list of country codes containing NO (Norway) silently turns into false. With “YAML 1.1-safe” on, the converter double-quotes those values; keys like GitHub Actions' on: are left alone.
{"country": "NO", "debug": "off", "released": "2026-10-18"}
country: "NO"
debug: "off"
released: "2026-10-18"Other strings that are always quoted
Values that would otherwise change type or break the syntax — "1.10" (would become the number 1.1), "null", "~", strings starting with *, &, ! or @, and strings containing : or # — are quoted in every mode, so the YAML always round-trips back to the same JSON.
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Frequently asked questions
Is my JSON uploaded anywhere?
No. The conversion runs entirely in your browser with JavaScript, so your JSON never leaves your device and isn't logged or stored.
Is the output valid YAML 1.2?
Yes. And with the YAML 1.1-safe option it also parses identically in YAML 1.1 parsers such as PyYAML.
Can I convert the YAML back to JSON?
Yes — use the YAML to JSON converter; values round-trip exactly.
Why are long strings not wrapped?
Line wrapping is turned off so strings stay on one line and diffs stay readable. Multi-line strings are written as YAML block scalars.
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