JSON to JSDoc Converter
Paste a JSON sample to instantly generate matching JSDoc @typedef blocks for editor autocomplete in plain JavaScript. Free online developer tool.
Paste JSON
JSDoc @typedef
JSDoc @typedef blocks will appear here...
Free JSON to JSDoc Converter
Paste a JSON sample to instantly generate matching JSDoc @typedef blocks — handy for adding editor autocomplete and type-checking to plain JavaScript without adopting TypeScript.
How to Use It
Paste any JSON object or array, or click "Load Example." The tool infers a type shape and emits one @typedef {Object} block per object level, listing each property with@property. Nested objects get their own named typedef, arrays becomeType[], optional properties use the bracketed [name] syntax JSDoc expects, and nullable properties get a leading ? on their type.
Example
Given {"name": "Ann", "age": 30, "tags": ["a","b"], "address": {"city": "NYC", "zip": null}}, the tool emits a RootAddress typedef whose zip property is documented as{?string} zip, plus a Root typedef whose tags property is{string[]} tags.
Common Use Cases
- Documenting the shape of a function's parameter or return value in plain JavaScript.
- Getting editor autocomplete and basic type checking via
// @ts-checkwithout migrating to TypeScript. - Adding self-documenting types to a JSON config or API payload consumed by a JS codebase.
FAQs
How do optional properties look in the output?
Following standard JSDoc convention, an optional property's name is wrapped in brackets, like@property {string} [zip], rather than using a separate optional-type marker.
Can I use these typedefs with @ts-check?
Yes — paste the generated @typedef blocks above a function and reference the type name in a @param {Root} or @returns {Root} tag; VS Code and other TypeScript-powered editors will pick it up automatically.
Is my JSON uploaded anywhere?
No — parsing and typedef generation happen entirely client-side in your browser. Nothing you paste is sent to a server.