JSON to React PropTypes
Paste JSON — get React PropTypes as you type. Nothing leaves your browser.
› More options & type detection
Convert JSON to any language
The same smart type inference, 27 output formats.
Types that match your real data
Built on the open-source quicktype engine, with quieter defaults and a friendlier editor.
- Optional fields detected
- Fields that are missing or null in some items become optional automatically.
- Merge many samples
- Paste JSON Lines or an array — every example contributes to one accurate type.
- Paste anything
- JavaScript objects, trailing commas, single quotes and comments are repaired for you.
- Sensible defaults
- No surprise enums or date classes — turn detection on only when you want it.
- Every option, every language
- All of React PropTypes’s generator settings, from naming style to framework annotations.
- Private & instant
- Runs in a background thread in your browser. Share links keep data in the URL only.
Frequently asked questions
How do I convert JSON to React PropTypes?+
Paste a JSON example on the left. CurlyJSON infers the structure — nested objects, arrays, optional fields and number types — and generates React PropTypes on the right as you type. Copy or download the result.
What if my samples have different fields?+
Paste several samples as JSON Lines (one JSON value per line) or as an array of objects. They are merged into one type, and fields missing from some samples become optional.
Can I paste a JavaScript object from the console?+
Yes. Unquoted keys, single quotes, trailing commas and comments are repaired automatically before the types are generated.
Is my data uploaded?+
No. The conversion runs entirely in your browser, in a background thread. Nothing is sent to a server.
Why don’t I see enums or date types?+
By default, string fields stay strings so the output matches your JSON exactly. Turn on “Detect enums” or “Detect dates” under Options to generate enum and date types.
Code generation uses quicktype (Apache-2.0 license).